Figures released by Northamptonshire Police show 424 drive-offs from forecourts were reported between December 2007 and the end of May, compared with 407 in the previous six months.

Jim Keary, manager at the W Grose garage in Queen's Park Parade, helped launch a Forecourt Watch partnership with Northamptonshire Police 12 months ago.

In that time he has had thousands of pounds worth of fuel stolen.

But he said: "We have such a good CCTV system now and the police respond so well, that we know people who drive off are likely to be caught and prosecuted.

"We have had some big drive-offs recently and that is a lot of petrol to replace in a year. Stealing fuel does happen, but because of the quality of our security it's not a huge problem for us.

"The main problem is the fact that we can't make money trading fuel at the moment, and the prices are scary."

The latest statistics were revealed as officers in the north of the county warned people to be on the lookout for suspicious activity around cars, after thefts of licence plates soared by almost 100 per cent.

So far this year, 129 stolen plates were reported, compared with 65 for the same period last year.

A Northamptonshire Police spokesman added: "We work closely with petrol stations looking for any links between crimes.

"Forecourt Watch was set up to be a single point of contact.

"When anyone leaves a garage without paying for fuel the garage will get in contact with us and help with our investigations, looking at things such as CCTV.

"The partnership is working well and we are continuing with that good work."

Anyone with information about number plate thefts c