The company's figures reveal the cost of theft from homes and businesses in the countryside rose by 6% in 1999, to around �168m a year.

One of the joys of living in the countryside was the low level of crime, but sadly it's not safe to leave doors unlocked today

NFU Mutual

NFU Mutual Underwriting Manager, Sid Gibson said: "Fear of crime, combined with the effects of the farm income crisis and other problems affecting life in the countryside, is leading to serious depression in many people and even a siege mentality in a minority."

The claims figures, disclosed today at the Royal Show in Warwickshire, come against the backdrop of the case of Norfolk farmer Tony Martin.

Tony Martin case raised issue of rural crime

Crime in the countryside has become a major political issue following the murder conviction Martin, who was jailed for shooting dead a teenage intruder who broke into his isolated farm.

NFU Mutual, which insures two thirds of UK farmers, believes many farmers have learned their lesson and are much more security conscious.

Soft target

NFU Mutual's statistics show the cost of equipment and vehicle thefts from farms fell from �93m in 1998 to �82m in 1999, although the company warns the message might not have got through to rural homeowners and businesses.

Mr Gibson said: "The rise in domestic theft does lend weight to the theory that improved security in urban areas, combined with the country's extensive motorway network, is leading would-be thieves to believe there are easy pickings to be had in rural areas.

"In past times one of the joys of living in the countryside was the low level of crime, but sadly it's not safe to leave doors unlocked today."

'More policing'

Martin's conviction sparked an outcry in some rural communities, which claim they are being left to defend themselves with little or no police protection.

The situation is believed to have been compounded by the closure of police sub-stations and a fall in the number of front-line officers in recent.

Pamela Oldfield, head of NFU Mutual's Risk Management Services, said the reduction in rural policing was a "contributory factor" in the rise in crime.

She added: "We would like to see more police in rural areas."