Gardeners fear that with economic conditions worsening and household budgets under strain, people are stealing produce in order to save themselves money at the checkouts.

A series of raids have prompted the Ottery St Mary allotment committee in Devon to launch evening patrols, with members visiting the set to keep an eye out for suspicious characters.

The town council has arranged for a lock to be put on the allotment gate and local police have asked nearby residents to report anything unusual.

Chairman of the committee, Adrian Foster, who has had raspberries, peas and runner beans stolen from his own allotment, said he had never experienced such high levels of thefts in the 22 years he has been there.

He said: "In times gone by, we occasionally had thefts of produce or equipment but it was negligible. It's definitely the case that over the last three or four months we've noticed that a lot more produce has gone missing.

"People are much more aware now of locally grown vegetables and they do carry quite a high premium. I think that's contributing to the problem because people see that kind of thing as more valuable than hitherto."

Torpoint Allotment Association in Cornwall has also introduced night time patrols. Chairman Peter McLaren said the regular inspections, introduced to tackle vandalism, were also deterring thieves.

Ayesha Wilkinson, from the South West Counties Allotment Association, said: "Thefts are becoming more common. It's produce more than anything now because of the price of food. It's definitely got worse over the last few months."

Mrs Wilkinson said it has been difficult to protect crops from produce thieves as most allotments are not very secure.