The party issued its second warning in a week of a downmarket city.

Firstly Bletchley councillor Alison Latham suggested at a council meeting that Milton Keynes could become a magnet for "every housing benefit claimant in the country" as a result of policies to boost the number of homes available for social rent.

Now party spokesman on expansion David Hopkins has warned of more housing gloom following reshuffling of regional planning responsibilities.

He was commenting after the announcement that housing and planning roles of the South East England Regional Assembly are to be switched to another unelected body, South East England Development Agency.

He said the 'South East' as viewed by a centralising Government was not a natural region, and it was "ludicrous" that it should cover an area including Milton Keynes, Oxford and Dover.

The Tories would continue to oppose Government housebuilding targets, especially given signs of an economic downturn.

"These flawed, top-down targets threaten to bulldoze hundreds of acres of farmland, worsen flood risk, increase carbon emissions and congestion, and potentially to build the sink estates of tomorrow."

Previously Cllr Latham queried reports that the number of homes planned for social rent was to be raised from 3,500 up to 20,000.

She asked council cabinet member for housing Irene Henderson: "Won't that make Milton Keynes a destination for every housing benefit claimant in the country?"

Cllr Henderson said: "I think that is a question that I am not prepared to reply to."

Cabinet colleague Cllr Sam Crooks called Cllr Latham's comment "grossly unfair and acutely distasteful".

Cllr Latham said later she was not being "nasty" about people on benefits. She was genuinely concerned that levels of housing for social rent might be disproportionate.

The Tories had "nothing against people on low incomes", she said.