The badges are for sale at �5 each

The design is based on a poster put up by a Fenland landowner with a picture of two crossed rifles and the words: "Warning - This Property is Protected by Tony Martin Security Services".

John O'Neill, 44, from Thorney, near Peterborough, Cambridgeshire, said although the poster was a joke, it helped deter burglars who had previously broken into his outbuildings and a scrap metal yard on his land.

It is tongue-in-cheek and also a good way to raise money for the campaign Peter Sainsbury, of the POW Trust

The London-based POW Trust is selling the badges for �5, although supporters should see it as a donation and pay as much as they can afford, said general secretary Peter Sainsbury.

The badges feature Martin's face, the rifles, and the words Tony Martin Security Services - although the company has never existed.

Mr Sainsbury said: "It is tongue-in-cheek and also a good way to raise money for the campaign."

The charity said the weapons represented the desperation of Martin supporters in rural areas who claim a lack of police protection means they have had to take the law into their own hands.

Martin shot dead 16-year-old Fred Barras in August 1999 and wounded Barras' accomplice Brendan Fearon during a burglary at his home in Emneth Hungate, Norfolk.

He was originally jailed for life after being convicted of murder and is due to be released from Highpoint Prison, Suffolk, on Monday.

The conviction was overturned on appeal and reduced to manslaughter and he was sentenced to five years in prison.

'No deterrent'

The Tony Martin Appeal Fund was started to pay the farmer's legal fees from previous court cases, and to fight the case against Fearon, who has been granted legal aid to sue Martin for damages for injuries he suffered during the burglary.

Mr O'Neill, 44, said he believed the badges were a good way of getting support to change the law to help householders who defend their own property.

"I think it's quite a good idea as eventually this is going to happen again.

"People have to have rights in their own homes. I don't agree with shooting or killing people, that's not the issue. But the trouble is the normal criminal has got no deterrent.