The M6 will be widened to four lanes between the Midlands and the North West as part of plans to tackle traffic congestion.

The �1bn plans were part of a package of public and private transport proposals announced by the government on Tuesday.

But the M6 plan has been condemned by environmentalists as fundamentally flawed.

Friends of the Earth (FotE) said the money would be better spent on improving rail links and encouraging people not to use their cars.

Our prediction is it will take 10 years for the M6 to be back to square one Frank Kennedy, Friends of the Earth

The measures were announced by Transport Secretary Alistair Darling on Tuesday.

But Frank Kennedy, of FotE, said the M6 plans marked a U-turn by the government.

He said: "The widening of the M6 is a government capitulation to some road dream that's never going to happen - it is a complete lack of leadership.

"Alistair Darling said when he came into office that he wasn't going to be pouring concrete over the countryside.

"But unfortunately this announcement about the M6 is going to be taking a 10-metre wide brush on either side and painting the whole of Cheshire with another layer of concrete."

He added increased road capacity would soon be taken up by more cars on the road.

He said: "If you look at the Newbury Bypass, four years on the journey time being saved is two minutes.

"Our prediction is it will take 10 years for the M6 to be back to square one."

The total UK transport package will cost more than �4bn with the North West.

Manchester's Metrolink tram system will be extended at a cost of �520m with three new lines linking Oldham and Rochdale, Ashton-under-Lyne and the Manchester Airport with the city centre.

Trams will also return to the streets of Liverpool by 2007 as part of plans to regenerate deprived areas such as Kirkby at a cost of �170m.

Millions will also be spent on local schemes including lengthening train platforms to take longer trains, and speeding buses through the traffic congestion.