feat(fuel): delete a test or mistaken meter reading with a reason

Clock scanner: double-tap the previous reading to remove the latest
scanner-entered reading. Fuel Logs and vehicle pages: double-click a
meter-only row to delete it. Reason, actor and values are logged.

Co-Authored-By: Claude Sonnet 5.5 <noreply@anthropic.com>

src/app/api/clock/vehicle-lookup/route.ts

@@ -26,7 +26,7 @@ export async function POST(request:Request) {
     const previous=await latestVehicleReading(pb,vehicle.id);
     return Response.json({vehicle:{id:vehicle.id,description:vehicle.description,qrCodeId:vehicle.qr_code_id,siteId:vehicle.site,
       unitType:vehicle.unit_type,transfer:scanSite!==vehicle.site,fuelLimits:vehicle.fuel_limits,costPerHour:vehicle.cost_per_hour},
-      hasPrevious:previous!==null,previousReading:previous?.odo_reading ?? null,previousLogId:previous?.id ?? null,
+      hasPrevious:previous!==null,previousReading:previous?.odo_reading ?? null,previousLogId:previous?.id ?? null,previousRemovable:previous?.source_system==="mega-clock",
       workDate:workDate(new Date().toISOString()),
     });
   } catch (error) {

src/app/api/clock/vehicle-reading-remove/route.test.ts

@@ -0,0 +1,35 @@
+import "@/test-utils/named-admin-session";
+import { beforeEach, describe, expect, it, vi } from "vitest";
+const mocks=vi.hoisted(()=>({vehicles:vi.fn(),logs:vi.fn(),getOne:vi.fn(),del:vi.fn(),release:vi.fn(),lock:vi.fn()}));
+vi.mock("@/lib/pb",()=>({pbAdmin:async()=>({
+  filter:(s:string,args:Record<string,unknown>)=>s.replace(/\{:(\w+)\}/g,(_,key)=>JSON.stringify(args[key])),
+  collection:(name:string)=>({getList:name==="vehicles"?mocks.vehicles:mocks.logs,getOne:mocks.getOne,delete:mocks.del}),
+})}));
+vi.mock("@/lib/fuel-import-store",()=>({createFuelImportStore:()=>({acquireLock:mocks.lock})}));
+import { POST } from "./route";
+const vehicle={id:"veh00000000001",site:"site0000000001",qr_code_id:"QR1",unit_type:"fuel"};
+const post=(changes:Record<string,unknown>={})=>POST(new Request("http://x",{method:"POST",body:JSON.stringify({qr_code_id:"QR1",log_id:"test",reason:"test reading",...changes})}));
+beforeEach(()=>{
+  Object.values(mocks).forEach(mock=>mock.mockReset());
+  mocks.vehicles.mockResolvedValue({items:[vehicle]});
+  mocks.logs.mockResolvedValue({items:[{id:"test",odo_reading:500,date_logged:"2026-10-26",source_system:"mega-clock"}]});
+  mocks.getOne.mockResolvedValue({id:"test",vehicle:vehicle.id,site:vehicle.site,odo_reading:500,source_system:"mega-clock"});
+  mocks.release.mockResolvedValue(undefined);mocks.lock.mockResolvedValue(mocks.release);
+});
+describe("scanner reading removal",()=>{
+  it("deletes the latest scanner-entered reading",async()=>{
+    const res=await post();expect(res.status).toBe(200);
+    expect(mocks.del).toHaveBeenCalledWith("test");expect(mocks.release).toHaveBeenCalledOnce();
+  });
+  it("needs a reason",async()=>{
+    expect((await post({reason:"x"})).status).toBe(400);expect(mocks.del).not.toHaveBeenCalled();
+  });
+  it("refuses a reading that is no longer the latest",async()=>{
+    expect((await post({log_id:"older"})).status).toBe(409);expect(mocks.del).not.toHaveBeenCalled();
+  });
+  it("refuses imported readings",async()=>{
+    mocks.logs.mockResolvedValue({items:[{id:"test",odo_reading:500,date_logged:"2026-10-26",source_system:"fuel-import"}]});
+    mocks.getOne.mockResolvedValue({id:"test",vehicle:vehicle.id,site:vehicle.site,odo_reading:500,source_system:"fuel-import"});
+    expect((await post()).status).toBe(409);expect(mocks.del).not.toHaveBeenCalled();
+  });
+});

src/app/api/clock/vehicle-reading-remove/route.ts

@@ -0,0 +1,47 @@
+import { z } from "zod";
+import { pbAdmin } from "@/lib/pb";
+import { requireApiUser, requireSiteAccess } from "@/lib/auth/guard";
+import { resolveScannableVehicle, latestVehicleReading, VehicleScanError } from "@/lib/vehicle-scan";
+import { createFuelImportStore } from "@/lib/fuel-import-store";
+
+export const runtime="nodejs";
+const schema=z.object({
+  qr_code_id:z.string().trim().min(1).max(160),log_id:z.string().min(1),
+  reason:z.string().trim().min(5).max(500),
+});
+
+/** Removes a mistaken or test meter reading entered through the clock scanner.
+ * Only the unit's latest reading can go, and only if the scanner wrote it, so
+ * imported and office-reviewed history is never touched from the kiosk. The
+ * reason, actor and the removed values are written to the server log. */
+export async function POST(request:Request) {
+  const user=await requireApiUser("clock");
+  if (user instanceof Response) return user;
+  const parsed=schema.safeParse(await request.json().catch(()=>null));
+  if (!parsed.success) return Response.json({error:"Give a reason of at least five characters."},{status:400});
+  const b=parsed.data;
+  let release:(()=>Promise<void>)|undefined;
+  try {
+    const pb=await pbAdmin();
+    const vehicle=await resolveScannableVehicle(pb,b.qr_code_id);
+    const denied=requireSiteAccess(user,vehicle.site);
+    if (denied) return denied;
+    release=await createFuelImportStore(pb).acquireLock();
+    const latest=await latestVehicleReading(pb,vehicle.id);
+    if (!latest || latest.id!==b.log_id) throw new VehicleScanError("Only the latest reading can be removed, and it has changed. Cancel and scan again.");
+    const log=await pb.collection("fuel_logs").getOne(latest.id);
+    if (log.vehicle!==vehicle.id) throw new VehicleScanError("That reading belongs to another unit.");
+    if (log.source_system!=="mega-clock") throw new VehicleScanError("Only readings entered on the clock scanner can be removed here. Ask the office to correct this one.");
+    await pb.collection("fuel_logs").delete(log.id);
+    console.warn("[vehicle-reading-remove]",JSON.stringify({vehicle:vehicle.id,qr:vehicle.qr_code_id,log:log.id,odo:log.odo_reading,
+      dateLogged:log.date_logged,site:log.site,actor:user.id,reason:b.reason,at:new Date().toISOString()}));
+    const next=await latestVehicleReading(pb,vehicle.id);
+    return Response.json({removed:log.id,previousReading:next?.odo_reading ?? null,previousLogId:next?.id ?? null,previousRemovable:next?.source_system==="mega-clock"});
+  } catch(error) {
+    const busy=error instanceof Error && /already running/.test(error.message);
+    return Response.json({error:error instanceof VehicleScanError ? error.message : busy ? "A fuel import or fleet update is running. Retry shortly." : "Could not remove the reading. Try again."},
+      {status:error instanceof VehicleScanError ? error.status : busy ? 409 : 503});
+  } finally {
+    if (release) await release().catch(error=>console.error("[vehicle-reading-remove] lock release failed",error));
+  }
+}

src/app/api/vehicles/[id]/readings/route.ts

@@ -66,3 +66,32 @@ async function save(request:Request,ctx:{params:Promise<{id:string}>},create:boo
 }
 export const PATCH=(request:Request,ctx:{params:Promise<{id:string}>})=>save(request,ctx,false);
 export const POST=(request:Request,ctx:{params:Promise<{id:string}>})=>save(request,ctx,true);
+
+/** Removes a mistaken or test reading. The reason and removed values go to the server log. */
+export async function DELETE(request:Request,ctx:{params:Promise<{id:string}>}){
+ const denied=await authorizeOperation(request);if(denied)return denied;
+ const user=await requireApiUser('dashboard');if(user instanceof Response)return user;
+ const {id}=await ctx.params;
+ const b=await request.json().catch(()=>null) as Record<string,unknown>|null;
+ const bad=(error:string,status=400)=>NextResponse.json({error},{status});
+ if(!b||typeof b!=='object'||Array.isArray(b))return bad('Body must be JSON');
+ if(typeof b.reason!=='string'||b.reason.trim().length<5||b.reason.length>2000)return bad('Add a reason of at least five characters.');
+ if(b.source!=='meter'&&b.source!=='weekly')return bad('Choose a meter reading or weekly sheet.');
+ if(typeof b.readingId!=='string'||typeof b.expectedUpdated!=='string')return bad('Refresh and reopen the reading.');
+ const pb=await pbAdmin();let release:(()=>Promise<void>)|undefined;
+ try{
+  release=await createFuelImportStore(pb).acquireLock();
+  const collection=b.source==='meter'?'fuel_logs':'plant_hours_log';
+  const row=await pb.collection(collection).getOne(b.readingId);
+  if(row.vehicle!==id)return bad('Not found',404);
+  const rowDenied=requireSiteAccess(user,row.site);if(rowDenied)return rowDenied;
+  if(plantReadingRevision(row)!==b.expectedUpdated)return bad('This reading changed. Refresh and reopen it before deleting.',409);
+  if(b.source==='meter'&&Number(row.litres)>0)return bad('This is a fuel fill, not a meter-only reading. Correct it instead of deleting.',409);
+  await pb.collection(collection).delete(row.id);
+  console.warn('[plant-reading-delete]',JSON.stringify({vehicle:id,collection,log:row.id,odo:row.odo_reading,dateLogged:row.date_logged,site:row.site,actor:user.id,reason:b.reason.trim(),at:new Date().toISOString()}));
+  return NextResponse.json({ok:true});
+ }catch(error){
+  console.error('[plant-reading-delete]',error);
+  return bad('Could not delete. Another fleet update may be running. Refresh before retrying.',409);
+ }finally{if(release)await release().catch(error=>console.error('[plant-reading-delete] lock release',error));}
+}

src/app/clock/fleet-scanner.tsx

@@ -133,6 +133,8 @@ export function FleetScanner({ onScan, sites = [] }: { onScan?: () => void; site
   // silently swap what's written. Refs capture the value at the
   // moment submit fires; the state is for UI.
   const gpsFixRef = React.useRef<GpsFix | null>(null);
+  // The last reading on file was entered on this scanner, so it may be removed.
+  const [previousRemovable, setPreviousRemovable] = React.useState(false);
   const lookupGeneration = React.useRef(0);
   const gpsGeneration = React.useRef(0);
   const confirmation = React.useRef<{requestId:string;previousId:string|null;day:string;payload?:Record<string,unknown>} | null>(null);
@@ -214,8 +216,10 @@ export function FleetScanner({ onScan, sites = [] }: { onScan?: () => void; site
           hasPrevious: boolean;
           previousReading: number | null;
           previousLogId: string | null;
+          previousRemovable?: boolean;
           workDate: string;
         };
+        setPreviousRemovable(ok.previousRemovable === true);
         confirmation.current={requestId:crypto.randomUUID(),previousId:ok.previousLogId,day:ok.workDate};
         setPhase({
           kind: "form",
@@ -329,6 +333,34 @@ export function FleetScanner({ onScan, sites = [] }: { onScan?: () => void; site
     [onScan, setPhase],
   );
 
+  // Removes the unit's latest scanner-entered reading (a test or a typo) so
+  // the next one can be entered. Returns an error message, or null on success.
+  const removePrevious = React.useCallback(
+    async (reason: string): Promise<string | null> => {
+      const current = phaseRef.current;
+      const context = confirmation.current;
+      if ((current.kind !== "form" && current.kind !== "submitError") || !context?.previousId) return "Nothing to remove";
+      try {
+        const res = await fetch("/api/clock/vehicle-reading-remove", {
+          method: "POST",
+          headers: { "Content-Type": "application/json" },
+          body: JSON.stringify({ qr_code_id: current.qrCodeId, log_id: context.previousId, reason }),
+        });
+        const body = await res.json();
+        if (!res.ok) return (body as { error?: string }).error ?? `Remove failed (${res.status})`;
+        const next = body as { previousReading: number | null; previousLogId: string | null; previousRemovable: boolean };
+        confirmation.current = { requestId: crypto.randomUUID(), previousId: next.previousLogId, day: context.day };
+        setPreviousRemovable(next.previousRemovable === true);
+        setPhase({ kind: "form", qrCodeId: current.qrCodeId, vehicle: current.vehicle, previousReading: next.previousReading });
+        onScan?.();
+        return null;
+      } catch {
+        return "Couldn't reach the server — try again";
+      }
+    },
+    [onScan, setPhase],
+  );
+
   // --- Camera + QR decode loop ----------------------------------------
   // Mount once. handleDecoded reads phaseRef.current — no re-binding.
   React.useEffect(() => {
@@ -485,6 +517,8 @@ export function FleetScanner({ onScan, sites = [] }: { onScan?: () => void; site
             phase={phase}
             gpsStatus={gpsStatus}
             gpsFix={gpsFix}
+            removable={previousRemovable}
+            onRemovePrevious={removePrevious}
             onSubmit={(reading) => {
               if (phase.kind !== "form" && phase.kind !== "submitError") return;
               const { qrCodeId, vehicle, previousReading } = phase;
@@ -522,11 +556,15 @@ function DialogBody({
   phase,
   gpsStatus,
   gpsFix,
+  removable,
+  onRemovePrevious,
   onSubmit,
 }: {
   phase: Phase;
   gpsStatus: "pending" | "ok" | "unavailable";
   gpsFix: GpsFix | null;
+  removable: boolean;
+  onRemovePrevious: (reason: string) => Promise<string | null>;
   onSubmit: (reading: number) => void;
 }) {
   if (phase.kind === "loading") {
@@ -571,6 +609,8 @@ function DialogBody({
         gpsFix={gpsFix}
         initialReading={phase.kind === "submitError" ? phase.reading : ""}
         submitError={phase.kind === "submitError" ? phase.message : null}
+        removable={removable}
+        onRemovePrevious={onRemovePrevious}
         onSubmit={onSubmit}
       />
     );
@@ -587,6 +627,8 @@ function FormBody({
   gpsFix,
   submitError,
   initialReading,
+  removable,
+  onRemovePrevious,
   onSubmit,
 }: {
   qrCodeId: string;
@@ -596,6 +638,8 @@ function FormBody({
   gpsFix: GpsFix | null;
   submitError: string | null;
   initialReading: string;
+  removable: boolean;
+  onRemovePrevious: (reason: string) => Promise<string | null>;
   onSubmit: (reading: number) => void;
 }) {
   const [value, setValue] = React.useState(initialReading);
@@ -640,7 +684,12 @@ function FormBody({
             This unit is registered to another site. Saving moves it here and logs its hours and readings against this site from now on.
           </div>
         )}
-        <PreviousReadingStrip previousReading={previousReading} suffix={suffix} />
+        <PreviousReadingStrip
+          previousReading={previousReading}
+          suffix={suffix}
+          removable={removable}
+          onRemove={onRemovePrevious}
+        />
         <GpsChip status={gpsStatus} fix={gpsFix} />
       </div>
 
@@ -709,10 +758,19 @@ function FormBody({
 function PreviousReadingStrip({
   previousReading,
   suffix,
+  removable,
+  onRemove,
 }: {
   previousReading: number | null;
   suffix: string;
+  removable: boolean;
+  onRemove: (reason: string) => Promise<string | null>;
 }) {
+  const [removing, setRemoving] = React.useState(false);
+  const [reason, setReason] = React.useState("");
+  const [busy, setBusy] = React.useState(false);
+  const [error, setError] = React.useState<string | null>(null);
+
   if (previousReading === null) {
     return (
       <div className="rounded-lg border border-dashed border-border bg-muted/40 px-3 py-2 text-xs text-muted-foreground">
@@ -720,14 +778,61 @@ function PreviousReadingStrip({
       </div>
     );
   }
+
+  if (removing) {
+    const canRemove = reason.trim().length >= 5 && !busy;
+    return (
+      <form
+        className="space-y-2 rounded-lg border border-red-500/40 bg-red-500/5 px-3 py-2"
+        onSubmit={async (e) => {
+          e.preventDefault();
+          if (!canRemove) return;
+          setBusy(true);
+          setError(null);
+          const failure = await onRemove(reason.trim());
+          setBusy(false);
+          if (failure) setError(failure);
+          else { setRemoving(false); setReason(""); }
+        }}
+      >
+        <p className="text-xs font-semibold">
+          Remove the previous reading ({previousReading.toLocaleString()} {suffix})?
+        </p>
+        <Input
+          value={reason}
+          onChange={(e) => setReason(e.target.value)}
+          placeholder="Reason, e.g. test reading"
+          aria-label="Reason for removing the reading"
+          autoFocus
+          className="h-10 bg-input/60 text-sm"
+        />
+        {error && <p className="text-xs font-medium text-red-600">{error}</p>}
+        <div className="flex gap-2">
+          <Button type="button" variant="outline" size="sm" className="flex-1" disabled={busy}
+            onClick={() => { setRemoving(false); setReason(""); setError(null); }}>
+            Keep it
+          </Button>
+          <Button type="submit" variant="destructive" size="sm" className="flex-1" disabled={!canRemove}>
+            {busy ? "Removing…" : "Remove reading"}
+          </Button>
+        </div>
+      </form>
+    );
+  }
+
   return (
-    <div className="flex items-center justify-between rounded-lg bg-muted/60 px-3 py-2">
+    <div
+      className={cn("flex items-center justify-between rounded-lg bg-muted/60 px-3 py-2", removable && "cursor-pointer select-none")}
+      onDoubleClick={removable ? () => setRemoving(true) : undefined}
+      title={removable ? "Double-tap to remove this reading" : undefined}
+    >
       <span className="text-xs font-semibold uppercase tracking-wide text-muted-foreground">
         Previous reading
       </span>
       <span className="font-mono text-base font-bold text-foreground">
         {previousReading.toLocaleString()} {suffix}
       </span>
+      {removable && <span className="sr-only">Double-tap to remove</span>}
     </div>
   );
 }

src/app/dashboard/plant/fuel-logs/fuel-logs-view.tsx

@@ -27,6 +27,7 @@ import {
   TableHeader,
   TableRow,
 } from "@/components/ui/table";
+import { DeleteReadingDialog } from "@/components/delete-reading-button";
 import { TableToolbar } from "@/components/table-toolbar";
 import { Pagination } from "@/components/ui/pagination";
 import { cn, formatCurrency, formatNumber } from "@/lib/utils";
@@ -41,6 +42,8 @@ import { ProjectPeriodBadge } from "@/components/project-period-badge";
 
 export interface FuelLogRow {
   id: string;
+  /** Revision token used when deleting a meter-only reading. */
+  updated?: string;
   dateLogged: string;
   vehicleId: string;
   vehicleDescription: string;
@@ -70,6 +73,8 @@ export function FuelLogsView({
   estimatedFuel?: boolean;
   sites: { id: string; name: string; project_code: string }[];
 }) {
+  const [deleting, setDeleting] = React.useState<FuelLogRow | null>(null);
+  const canDelete = (r: FuelLogRow) => r.litres === 0 && !!r.vehicleId && !!r.updated && !r.hasDocument;
   const [siteFilter, setSiteFilter] = React.useState<string>("all");
   const [unitFilter, setUnitFilter] = React.useState<UnitFilter>("all");
   const [sourceFilter, setSourceFilter] = React.useState<SourceFilter>("all");
@@ -241,7 +246,10 @@ export function FuelLogsView({
               </TableHeader>
               <TableBody>
                 {pageRows.map((r) => (
-                  <TableRow key={r.id}>
+                  <TableRow key={r.id}
+                    onDoubleClick={canDelete(r) ? () => setDeleting(r) : undefined}
+                    title={canDelete(r) ? "Double-click to delete this meter reading" : undefined}
+                    className={canDelete(r) ? "cursor-pointer" : undefined}>
                     <TableCell className="text-xs tabular-nums">
                       {r.dateLogged
                         ? format(parseISO(r.dateLogged), "yyyy-MM-dd")
@@ -318,6 +326,16 @@ export function FuelLogsView({
               </TableBody>
             </Table>
           )}
+          {deleting && (
+            <DeleteReadingDialog
+              open
+              onOpenChange={(v) => { if (!v) setDeleting(null); }}
+              vehicleId={deleting.vehicleId}
+              readingId={deleting.id}
+              updated={deleting.updated!}
+              label={`${deleting.vehicleDescription} · ${deleting.odoReading != null ? formatNumber(deleting.odoReading) : "—"} on ${deleting.dateLogged ? format(parseISO(deleting.dateLogged), "yyyy-MM-dd") : "—"}`}
+            />
+          )}
         </CardContent>
         {sorted.length > PAGE_SIZE && (
           <div className="border-t border-border px-4 py-3">

src/app/dashboard/plant/fuel-logs/page.tsx

@@ -6,6 +6,7 @@ import { loadFuelPrices } from "@/lib/fuel-prices";
 import { filterOpt, siteFilter, siteFilterAllowingUnassigned, type SearchParams } from "@/lib/site-scope";
 import { getSiteScope } from "@/lib/site-scope-server";
 import { FuelLogsView, type FuelLogRow } from "./fuel-logs-view";
+import { plantReadingRevision } from "@/lib/plant-reading-revision";
 import { deriveProjectPeriodLabel } from "@/lib/project-calendar";
 
 export const dynamic = "force-dynamic";
@@ -59,6 +60,7 @@ export default async function FuelLogsPage({
       (l.fuel_sheet ?? "");
     return {
       id: l.id,
+      updated: plantReadingRevision(l as unknown as Record<string, unknown>),
       dateLogged: l.date_logged ?? "",
       vehicleId: l.vehicle ?? "",
       vehicleDescription: v?.description ?? "(unknown)",

src/app/dashboard/plant/vehicles/[vehicleId]/page.tsx

@@ -6,6 +6,7 @@ import { notFound } from "next/navigation";
 import { ArrowLeft } from "lucide-react";
 import { pbAdmin } from "@/lib/pb";
 import { parseFuelLimit } from "@/lib/fuel-variance";
+import { plantReadingRevision } from "@/lib/plant-reading-revision";
 import { compareMeterLogs } from "@/lib/metrics/plant-hours";
 import { fuelFillSeries, averageFuelEfficiency } from "@/lib/metrics/fuel-fill-series";
 import { loadFuelPrices } from "@/lib/fuel-prices";
@@ -116,6 +117,7 @@ export default async function VehicleDetailPage({
       cumulativeCost,
       cost,
       projectCode: logSiteById[log.site] || vehicleProjectCode,
+      updated: plantReadingRevision(log as unknown as Record<string, unknown>),
     });
   }
 
@@ -171,6 +173,7 @@ export default async function VehicleDetailPage({
       />
       <VehicleDetailView
         vehicleId={vehicleId}
+        canManage={canManage}
         points={points}
         kpis={{
           totalLitres,

src/app/dashboard/plant/vehicles/[vehicleId]/vehicle-detail-view.tsx

@@ -1,6 +1,7 @@
 "use client";
 
 import * as React from "react";
+import { DeleteReadingDialog } from "@/components/delete-reading-button";
 import { format, parseISO } from "date-fns";
 import { useRouter } from "next/navigation";
 import {
@@ -40,6 +41,8 @@ export interface VehicleDetailPoint {
   cumulativeCost: number;
   cost: number;
   projectCode: string;
+  /** Revision token for editing/deleting meter-only readings. */
+  updated?: string;
 }
 
 interface VehicleDetailKpis {
@@ -106,7 +109,9 @@ export function VehicleDetailView({
   kpis,
   vehicle,
   vehicleId,
+  canManage = false,
 }: {
+  canManage?: boolean;
   points: VehicleDetailPoint[];
   kpis: VehicleDetailKpis;
   vehicleId: string;
@@ -123,6 +128,7 @@ export function VehicleDetailView({
   };
 }) {
   const [historyPage, setHistoryPage] = React.useState(1);
+  const [deleting, setDeleting] = React.useState<VehicleDetailPoint | null>(null);
   const historyPageCount = Math.max(1,Math.ceil(points.length/25));
   const safeHistoryPage = Math.min(historyPage,historyPageCount);
   const historyPoints = [...points].reverse().slice((safeHistoryPage-1)*25,safeHistoryPage*25);
@@ -446,7 +452,10 @@ export function VehicleDetailView({
                   {historyPoints.map((p) => {
                     const km = p.kmPerL !== null ? p.kmPerL * p.litres : null;
                     return (
-                      <tr key={p.id} className="border-b border-border last:border-0">
+                      <tr key={p.id}
+                        onDoubleClick={canManage && p.litres === 0 && p.updated ? () => setDeleting(p) : undefined}
+                        title={canManage && p.litres === 0 && p.updated ? "Double-click to delete this meter reading" : undefined}
+                        className={cn("border-b border-border last:border-0", canManage && p.litres === 0 && p.updated && "cursor-pointer")}>
                         <td className="px-3 py-2 text-xs tabular-nums">
                           {p.date ? format(parseISO(p.date), "yyyy-MM-dd") : "—"}
                           <span className="block text-muted-foreground">{p.projectCode || "—"}</span>
@@ -483,6 +492,16 @@ export function VehicleDetailView({
               </table>
             </div>
           )}
+          {deleting && (
+            <DeleteReadingDialog
+              open
+              onOpenChange={(v) => { if (!v) setDeleting(null); }}
+              vehicleId={vehicleId}
+              readingId={deleting.id}
+              updated={deleting.updated!}
+              label={`${formatNumber(deleting.odoReading)} on ${deleting.date ? format(parseISO(deleting.date), "yyyy-MM-dd") : "—"}`}
+            />
+          )}
           {points.length > 0 && <Pagination className="border-t border-border p-4" page={safeHistoryPage} pageCount={historyPageCount} pageSize={25} total={points.length} onPageChange={setHistoryPage} label="Newest first" />}
         </CardContent>
       </Card>

src/components/delete-reading-button.tsx

@@ -0,0 +1,54 @@
+"use client";
+import * as React from "react";
+import { useRouter } from "next/navigation";
+import { Button } from "@/components/ui/button";
+import { Input } from "@/components/ui/input";
+import { Dialog, DialogContent, DialogDescription, DialogHeader, DialogTitle } from "@/components/ui/dialog";
+
+/** Removes a mistaken or test meter reading, with a reason that is logged server-side.
+ * Opened by double-clicking a meter-only row, so there is no visible delete control. */
+export function DeleteReadingDialog({ vehicleId, readingId, updated, label, open, onOpenChange }: {
+  vehicleId: string; readingId: string; updated: string; label: string;
+  open: boolean; onOpenChange: (open: boolean) => void;
+}) {
+  const router = useRouter();
+  const setOpen = onOpenChange;
+  const [reason, setReason] = React.useState("");
+  const [busy, setBusy] = React.useState(false);
+  const [error, setError] = React.useState("");
+  const canDelete = reason.trim().length >= 5 && !busy;
+
+  async function remove(e: React.FormEvent) {
+    e.preventDefault();
+    if (!canDelete) return;
+    setBusy(true); setError("");
+    try {
+      const res = await fetch(`/api/vehicles/${vehicleId}/readings`, {
+        method: "DELETE", headers: { "content-type": "application/json" },
+        body: JSON.stringify({ source: "meter", readingId, expectedUpdated: updated, reason: reason.trim() }),
+      });
+      const data = await res.json();
+      if (!res.ok) throw new Error(data.error || "Could not delete");
+      setOpen(false); setReason(""); router.refresh();
+    } catch (err) { setError(err instanceof Error ? err.message : "Could not delete"); }
+    finally { setBusy(false); }
+  }
+
+  return (
+    <>
+      <Dialog open={open} onOpenChange={v => { if (!busy) setOpen(v); }}>
+        <DialogContent>
+          <DialogHeader>
+            <DialogTitle>Delete this reading?</DialogTitle>
+            <DialogDescription>{label}. Use this for a test or mistaken meter reading so the next real one can be recorded.</DialogDescription>
+          </DialogHeader>
+          <form onSubmit={remove} className="space-y-3">
+            <Input value={reason} onChange={e => setReason(e.target.value)} placeholder="Reason, e.g. test reading" aria-label="Reason for deleting" maxLength={2000} autoFocus />
+            {error && <p role="alert" className="text-sm text-destructive">{error}</p>}
+            <Button type="submit" variant="destructive" disabled={!canDelete}>{busy ? "Deleting…" : "Delete Reading"}</Button>
+          </form>
+        </DialogContent>
+      </Dialog>
+    </>
+  );
+}

src/components/plant-reading-review.tsx

@@ -20,6 +20,10 @@ export function PlantReadingReview({vehicleId,reading,sites,reason,create=false}
   const payload={source:reading.source,readingId:reading.id,expectedUpdated:reading.updated,site,reason:note,...(reading.source==='meter'?{date_logged:new Date(date+'+02:00').toISOString(),odo_reading:Number(odo),meter_reset:reset}:{start_date:start,end_date:end,start_hours:Number(startMeter),end_hours:Number(endMeter),cost_per_hour:Number(rate)})};
   const res=await fetch(`/api/vehicles/${vehicleId}/readings`,{method:create?'POST':'PATCH',headers:{'content-type':'application/json'},body:JSON.stringify(payload)});const data=await res.json();if(!res.ok)throw Error(data.error||'Could not save');setOpen(false);router.refresh();
  }catch(e){setError(e instanceof Error?e.message:'Could not save');}finally{setSaving(false);}}
+ async function remove(){if(!window.confirm('Delete this reading? This cannot be undone.'))return;setError('');setSaving(true);try{
+  const res=await fetch(`/api/vehicles/${vehicleId}/readings`,{method:'DELETE',headers:{'content-type':'application/json'},body:JSON.stringify({source:reading.source,readingId:reading.id,expectedUpdated:reading.updated,reason:note})});const data=await res.json();if(!res.ok)throw Error(data.error||'Could not delete');
+  setOpen(false);router.refresh();
+ }catch(e){setError(e instanceof Error?e.message:'Could not delete');}finally{setSaving(false);}}
  function begin(){setReset(reading.review_history?.at(-1)?.after?.meter_reset===true);setSite(reading.site);setDate(localTime(reading.source_logged_at || reading.date_logged || ''));setOdo(String(reading.odo_reading??''));setStart(reading.start_date?.slice(0,10)??'');setEnd(reading.end_date?.slice(0,10)??'');setStartMeter(String(reading.start_hours??''));setEndMeter(String(reading.end_hours??''));setRate(String(reading.cost_per_hour??''));setNote('');setError('');setOpen(true);}
  return <><Button variant="outline" size="sm" onClick={begin}>{create?'Add Missing Reading':reason?'Review':'Edit Reading'}</Button><Dialog open={open} onOpenChange={v=>{if(!saving)setOpen(v);}}><DialogContent><DialogHeader><DialogTitle>{create?'Add Missing Reading':reading.source==='weekly'?'Review Weekly Sheet':'Review Meter Reading'}</DialogTitle><DialogDescription>Use verified source records. Saving recalculates hours and cost; any remaining issue stays marked for review.</DialogDescription></DialogHeader>
  {reason&&<p className="rounded-md border border-border p-3 text-sm">{reason}</p>}
@@ -32,6 +36,7 @@ export function PlantReadingReview({vehicleId,reading,sites,reason,create=false}
  {error&&<p role="alert" className="text-sm text-destructive">{error}</p>}
  <Button type="submit" disabled={saving}>{saving?'Saving…':create?'Save Reading':'Save Correction'}</Button>
  </form>
+ {!create&&<div className="space-y-2 border-t border-border pt-3"><p className="text-xs text-muted-foreground">Entered by mistake or as a test? Enter a reason in the note above, then delete it so the next reading can be recorded.</p><Button type="button" variant="destructive" size="sm" disabled={saving||note.trim().length<5} onClick={()=>void remove()}>{saving?'Working…':'Delete Reading'}</Button></div>}
  {!!reading.review_history?.length&&<details className="text-xs"><summary className="cursor-pointer">Correction History ({reading.review_history.length})</summary>{reading.review_history.map((h,i)=><div key={i} className="mt-2 border-t border-border pt-2"><p>{h.at.slice(0,10)} · {h.actor}</p><p>{h.reason}</p><pre className="mt-1 whitespace-pre-wrap break-all text-muted-foreground">{JSON.stringify({before:h.before,after:h.after},null,2)}</pre></div>)}</details>}
  </DialogContent></Dialog></>;
 }