Midland farmers said they are “stuck between a rock and a hard place” as thefts of red diesel have risen by nearly a third since January.

The price of industrial diesel, commonly used by farm vehicles but not available from most petrol stations, has almost doubled in the first four months of the year, from 37p to 65p a litre.

But the death of farmer’s wife Rosemary Dove, who suffered a heart attack as she dialled 999 when diesel was being stolen from a pump at their farm in Middleham, County Durham last week, has made many fearful for their own safety.

A survey conducted by rural insurer NFU Mutual revealed the number of diesel thefts shot up by 30 per cent between January and April as the credit crunch and fuel crisis tighten their grip on rural businesses and communities.

As well as fuel, farmers are faced with steep increases in fertiliser and production costs of potatoes have risen by 12 per cent, while dairy farmers are spending 21 per cent more on necessities like grain feed.

Tim Price, spokesman for NFU Mutual, said: “I spoke to a farmer in Pershore who had red diesel stolen from his farm last week, and another farmer near Stratford-upon-Avon, who’s had two similar fuel thefts and as a result has had to stop storing diesel on his land, which is a real hassle for him.

“It’s not as if he can just take his tractor or other machinery to a local garage, as red diesel is only sold at selected depots.

“A survey of our 300 offices across the UK shows the number of diesel thefts reported to us has risen by 30 per cent between January and April, as the price of fuel continues to go up so has the level of diesel thefts. They’ve responded to the price hikes in the same way they did when the price of scrap metal went up last year, which saw a significant increase in thefts of copper piping, lead roofing, steel and iron.

“We’re also getting feedback from farmers, especially after Rosemary’s Dove’s death in County Durham, that personal security is one of their biggest worries.

“However, the flipside to that is, as thieves are quite brazen and may have accomplices, they are also worried about being prosecuted if they try and tackle any intruders. It’s a very tough time right now for the farming industry.”

Last month thieves broke into a council depot in Honington, south Warwickshrie, and forced the filler cap off a vehicle and stole 200 litres of diesel, and offenders stole two caravans off a farm in Charlescote after forcing off wheel clamps.

Farmer Paul Rice, chairman of Warwickshire NFU, said thefts like this only served to push up farming costs.

Mr Rice said: “The average cost of agricultural production rose by 16.5 per cent between September 2007 and March 2008, and farmers are being squeezed by these increased costs, and I am aware of local incidents were they have been targeted by thieves.

“There is a fear that if they do confront an intruder or intruders on their premises that if they’re not killed, they may be prosecuted if, in order to protect their property, they defend themselves with force. I don’t think personal safety has ever been such an important issue for farmers.”