Howard Thomas, probation chief between 1985 and 1996, said the plans for a prison, with Wrexham named as one of four potential locations on a shortlist on Wednesday, should be opposed on a number of grounds.

He claimed the move would have an adverse impact on the region with more and more potential reoffenders being released into the community.

He said: "What is incredible about the announcement to go ahead with new prison building in North Wales and other settings, is that it flies in the face of comments made earlier by Jack Straw and his Scottish counterpart, Kenny MacAskill, to the effect that you can't build your way out of prison overcrowding'.

"It beggars belief that at a time of economic downturn literally billions of borrowed money – £2.4 billion latest estimate – should be spent locking up more and more people.

"This is taking place against a backdrop of falling crime figures and with reference to North Wales, last week's figures show we have less personal crime here than anywhere in England and Wales.

"But perhaps the most compelling argument against additional prison capacity is that prisons generate crime by churning out more and more people who are become family-less, homeless, jobless and ready to offend again." Wrexham's MP, Ian Lucas, has also objected to the plans claiming the proposed site, on the town's former Firestone factory, is wrong for a number of reasons, including poor transport links.

Mr Lucas said he would be writing to the Ministry of Justice again as part of the formal consultation process, which runs until October 31.

Prisons minister David Hanson announced four potential sites in Wales for the proposed jail including Wrexham. He added that any further sites put forward in response to the consultation would be investigated if considered to have potential.

According to a study conducted by Iolo Madoc-Jones, principal lecturer in the criminal justice and social welfare department at Glyndwr University, Wrexham, a prison would lead to a reduction in crime in the immediate vicinity and create 'significant benefits' for the local economy.

l The big prison debate – Pages 14-15