Plans for a 50-mile toll motorway linking Birmingham and Manchester have been condemned by MPs.
The Transport Select Committee, chaired by Labour backbencher Gwyneth Dunwoody, accused Ministers of ignoring the results of a major consultation.
More than 95 per cent of responses were opposed to the plans for a privately-built two-lane road. But instead of scrapping the plans, the Department for Transport ordered a new feasibility study.
In a new report, the Committee said: "It appears the Department had already made the decision to proceed, and that the consultation was cosmetic."
In their hard-hitting report, the MPs added: "There was a 50 to one response on the part of the public to extending the M6 Toll road north of Birmingham to Manchester but further feasibility studies have been ordered.
"The Department should explain the point of consulting the public when it simply ignores the result."
Approximately 9,500 responses were received by October 2004, Transport Ministers asked the Highways Agency, the Government body responsible for Britain's road network, to carry out a new feasibility study.
Last night a spokesman for the Department for Transport said: "It was certainly not cosmetic.
"It was a thorough consultation to assess people's views, and there is more work being done now.
"There was no real consensus, and so we are doing more work to present options to Ministers.
"We don't go through the time and expense of a major consultation just for show."
The 50-mile M6 Expressway would run parallel to the M6 from junction 11A, near Cannock in Staffordshire, to junction 19, near Knutsford in Cheshire.
It would be only the second pay-as-you-go road, following the opening in December 2003 of the 27-mile M6 Toll.
If it goes ahead, the scheme would replace plans to widen the junctions 11 to 19 stretch of the existing M6 from three lanes to four.
MP David Kidney (Lab Stafford), who opposes both schemes, said: "The consultation was flawed and the Department has recognised that, but I don't think the decision had already been made to build the Expressway.
"The Department now is pursuing both proposals and gathering opinions, so it is wrong to say it had made up its mind last year."
A series of seminars have been organised for business leaders and other stakeholders to examine the options and present feedback to officials.
As well as the creation of a new Expressway, the choices are two forms of widening the existing road - either by adding an extra lane at either side, which would be the most disruptive option, or building new carriageways on one side and shifting the central reservation over to create the four lanes in each direction.
Transport Secretary Alistair Darling has warned that Britain eventually needs a national road-pricing strategy to avoid gridlock.
However, takeup of the existing M6 Toll has been patchy and vehicle numbers last year were 15.3 per cent down on 2004.