The number of fuel thefts has doubled in a year as drivers turn to extreme measures to try to cope with soaring prices at the pumps.

Statistics released by Sussex Police show that thieves were striking at a rate of almost once a day during May and the start of June.

In May there were 25 thefts, more than double the 12 in the same month in 2007. There were another five by June 4, the cut off point for the figures.

Lewes MP Norman Baker, the Liberal Democrats transport spokesman, said: "This is a very regrettable development. It does indicate that the price of fuel is having an affect.

"It is a very selfish act by those involved and a dangerous one too because it potentially leave people stranded."

The thefts in the police statistics were all incidents where fuel had been siphoned from vehicles while they were parked overnight.

The figures showed that the crimes had been happening at average of more than 20 a month in the past year with the crook particular active in May and in March when there were also 25 incidents.

There was a major spate in November when thieves struck on 42 occasions.

Roger McArthur, chairman of Sussex van driver's group Traders Against Parking Persecution, said he was not surprised by the increase.

He said: "It was inevitable this was going to happen. It is a difficult time at the moment, petrol prices are going up but people have got less money coming in because the building trade is starting to dry up."

He said he had heard of people who had petrol stolen from them and many tradesman had been buying lockable petrol caps to protect themselves from falling victim.

Fuel prices have soared by up to 30p per litre in the past six months, increasing the cost of filling an average car's tank by more than £10.

Elsewhere in the country there have been several reported cases of thefts of red diesel from farms. The fuel is taxed at a lower rate than normal diesel and is only legally allowed to be used for a agricultural vehicles.

Insurance group NFU Mutual said it had 50 claims for stolen fuel in the first five months of this year, costing £100,000.

It has prompted many farms to improve their security measures. Nickel Farm, in Chatham, Kent has installed CCTV around its premises and employed a guard to monitor its fleet of vans and fuel tanks.