They say dwindling confidence in the police must prompt the government to "look seriously" at the consequences of the Tony Martin case.

Ex-Cabinet ministers Gillian Shephard, John McGregor, David Prior and Keith Simpson voiced their fears in a joint statement issued following a government pledge to inject cash into rural policing.

"Many are saying that, like Tony Martin, they too would have defended themselves if the police were unable to help them," the statement said.

"The possibility of a breakdown in law and order in our countryside is real. Action is needed now."

Gillian Shephard represents Norfolk South West, the constituency of Tony Martin, who is appealing against his conviction for murdering a teenage burglar.

Clarity sought

The MPs' call for action also follows a plea by Jim Wilson, chairman of the Norfolk Police Authority, for greater clarity in self-defence laws.

Ministers are proposing to tackle rural fears on crime in the wake of the Tony Martin case by offering extra cash for policing isolated areas.

The extra grants - likely to run into tens of millions - come after a Home Office study last year into the problems of population density and policing, according to reports.