The Government's own environmental advisers have rejected a proposed £2 billion toll road alongside the M6 north of Birmingham.
The Department for Transport and Highways Agency have already attracted criticism for not inviting householders blighted by the M6 Expressway scheme to a "stakeholder seminar" in Penkridge, Staffordshire, yesterday.
Now a joint letter to Transport Minister Stephen Ladyman from the Countryside Agency, English Nature, English
Heritage and Environment Agency - all Government quangos - has criticised the scheme because of its impact on the environment.
They wrote: "The Statutory Bodies' shared position regarding the M6 Expressway is that the proposal should be rejected due to its potential impacts on the built and historic environment and its likely severe impacts on the surrounding landscape, designated sites, waterways, flood plains and on local communities.
"We are concerned that the feasibility study is going ahead despite the significant level of opposition on environmental grounds expressed by consultees to the proposal."
There are currently only "indicative" plans for the new 50-mile toll road, between Cannock and Knutsford, Cheshire.
The HA has admitted the Expressway could run on either side of the current M6.
It is gathering opinions from local authorities and other bodies in order to decide between a privately-built toll road or widening the M6 through state funds. A final decision is expected in the summer.
The Campaign to Protect Rural England has branded the plans a "countryside munching monster".
It is "dismayed" that there is no non-road building option being considered.
Paul Hamblin, CPRE's transport spokesman, said: "The Government consulted on the idea of a new tolled motorway and 9,313 of the 9,528 respondents objected to it.
"Astonishingly, Ministers have said there is no consensus on the idea. Government Ministers and the HA say the choice is between a bigger M6 or a new tolled motorway.
"But the 'third way' is to better manage traffic without destroying the countryside with new road building."