Hampshire police drivers have cost taxpayers more than £14,000 - by topping up patrol cars with the wrong fuel.
The tally is revealed in research that shows forces across the UK have spent almost £400,000 repairing cars after officers filled them from an incorrect pump.
The cost in Hampshire was the fourth highest among forces that responded to a Freedom of Information Act request that revealed there have been more than 2,100 embarrassing mishaps since 2011. The average repair cost is £181 per incident.
It works out at more than one incident per day, with the problem getting worse. Figures for 2015 show the highest rate of incidents in the last five years.
With an average repair cost of £181.68 for every incident, it has costs the police forces a total of £390,061, according to the data obtained by Auto Express.
The Met Police were the biggest culprit, racking up £167,118 in repair costs, with Kent Police (£25,629) the second worst.
At the opposite end, officers in Greater Manchester and Northern Ireland forces have completely avoided such fuelling fiascos. This achievement has put down to their use of bunkered fuel depots and pre-programmed keys, which help prevent the wrong fuel being used.
Luke Bosdet, a spokesman for the AA, told Auto Express: “It’s an annoying and avoidable mistake that will take a vehicle off the road and place an extra burden on stretched resources.
“But it shows that police officers are human like the rest of us. Stress and pre-occupied minds are often the cause of misfuelling mistakes, which fleet managers can try to beat with fuel-tank labelling and reminders.”
UK’s five worst offenders:
1. Metropolitan Police - total bill £167,118
2. Kent - total bill £25,629
3. Derbyshire - total bill £16,078
4. Hampshire - total bill £14,070
5. Devon and Cornwall - total bill £13,118