The transport secretary has told MPs that the government is considering a new toll road to the North West.

Alistair Darling outlined proposals for a new "pay-as-you-go" motorway in a Commons statement on Tuesday.

He said the Department for Transport would consult on the plan to extend the recently-opened toll road - which already shortcuts a busy stretch of the M6 around Birmingham - all the way to Manchester.

The "expressway" would be built instead of a planned widening of the M6 and Darling said it would provide the same benefits at a lower cost, with more money recouped for public transport.

A study of the new road's impact has shown it carries around a fifth of cars on the route and has led to a 10 per cent reduction in traffic on the existing roads around it.

"All this has been welcomed by business," Darling said.

He also moved to appease environmental campaigners by giving the go-ahead to trials of car sharing only lanes on some key commuter routes.

The transport secretary said both steps were "necessary".

"First we need to make better use of our existing roads," he said.

"And secondly we need to address the need for additional capacity.

"Car pool lanes could play a key role in reducing congestion on key commuter routes."

Fury

However green groups have reacted furiously to the news as it emerged on Tuesday.

It was described as a U-turn by Friends of the Earth.

The environmental lobby group said it was "angry and bitterly disappointed".

"When it came to power, Labour said that we can't build our way out of congestion and promised to cut the amount of traffic on our roads," FoE transport campaigner Tony Bosworth said.

"But the government has now caved in to the roads lobby. This new toll motorway will encourage more people to drive and won't solve our transport problems."

Although the current government gave its blessing to the first M6 toll scheme, the original plans were commissioned by the previous Conservative administration.

But pressures on the road network, alongside the full capacity of the railways and the success of London's congestion charge, has encouraged Labour to rethink its strategy on road building and pricing.

Reaction

Shadow transport secretary Tim Yeo said ministers had backed off from giving full support to the level of road building that is required.

"Since 1997, this government has been trying to force motorists off the roads by increasing taxes on the driver and doing little to ease congestion or improve public transport," the Conservative said.

"We welcome the government's realisation that their approach was not working but fear that this gesture to motorists is too little too late.

"What we need now is a clear indication as to when this toll road will be ready and where else they intend to build new roads."

Liberal Democrat transport spokesman John Thurso said the government lacked a clear strategy.

"Privatised motorways are not the answer to Britain's long term congestion problems," he said. " New roads are environmentally damaging and very expensive.

"The government has already admitted that we simply cannot build Britain out of jams. 

"The real challenge is to move from indiscriminate taxation of car ownership towards targeted taxation of car use through road pricing.

"Alistair Darling should be offering a structured and well thought out plan for national road charging, not piecemeal solutions."