More than half of the 11 proposals for eco-towns that the government is considering may be financially unviable, an official report has revealed

The research, carried out by consultant Pricewaterhouse Coopers for the communities department, found that three of the proposed schemes, in particular, would be unlikely to go ahead at all in the current market. These are the proposed towns in North West Bicester, Rossington in South Yorkshire and the St Austell China Clay community in Cornwall.

The report says the St Austell scheme, promoted by mining company Imerys, would need “substantial levels of public subsidy” to be developed, as it was up to £190m in the red.

Proposals at Ford Airfield, Weston Otmoor and Whitehill Bordon also have significant uncertainties over their viability.

Eleven developers are still bidding for a place on the government’s eco-town programme, originally charged by prime minister Gordon Brown in September 2007 to deliver 10 new zero-carbon communities.