The Government last night appeared to prepare the ground for a humiliating retreat from controversial proposals to build thousands of ecohomes in Sussex and across the country.

Housing Minister Margaret Beckett downgraded the prospects of the flagship ecotown programme as she extended the deadline for the latest public consultation.

Last November, the Government kept alive proposals for 5,000 new zerocarbon homes on a former airfield at Ford, between Littlehampton and Arundel, giving the scheme a Grade B in a ministerial assessment of its likely impact on the community, economy and environment.

Ms Beckett said she did not expect all the locations to be given the goahead, adding: "The eco-town standards are tough and I think some of these shortlisted schemes could struggle to meet them."

However, in the most pessimistic ministerial assessment of the building programme yet, she has now raised the prospect of every scheme being halted in its tracks.

Ms Beckett said: "It is vital we identify the right locations for these ecotowns and I will not support any proposal that our assessment and consultation concludes is unsuitable."

A senior Government source last night confirmed it was possible that not a single one of the 11 remaining schemes which include Ford would see the light of day.

The Department for Communities and Local Government said it was pushing back the deadline for residents to respond to the Government's second consultation from Friday until April 30 after campaigners in Warwickshire failed to defeat the eco-town programme in court.

Ms Beckett said: "I know this is an issue that raises a lot of strong opinion on all sides.

"I have extended the deadline to ensure that all parties, irrespective of their views, are given the full opportunity to have their say and I urge everyone to respond."