A network of toll-paying "super-motorways" between Britain's major cities is being considered by the government, according to reports.

The new roads would be built close to existing motorways and be part of a scheme designed to prevent gridlock descending on the nation's roads.

The proposals were made by Lord Birt, Prime Minister Tony Blair's transport special advisor and former BBC director-general, who suggests the "premium roads" would have few exits and serve as high-speed links.

A spokesman for the Department of Transport played down the reports, saying: "We don't believe that a system of road charging could be introduced this decade. Accordingly the government has no plans to do so."

It is also suggested that Lord Birt has proposed plans for rail freight lines from northern England to the Channel Tunnel and a high-speed passenger service from the north to the south coast.

Congestion charges

Based on the French peage system, the likely routes for the new motorways would be between London, Birmingham, Manchester and possibly Bristol.

It is also suggested that there could be an outer London ring road beyond the M25, reaching as far as Milton Keynes.

Lord Birt is also thought to support the use of congestion charges, where drivers are forced to pay to enter busy towns.

Such a scheme has already been adopted by London Mayor Ken Livingstone and other local councils have been given the power to introduce their own schemes.

Confidential

In 18 months time Britain's first toll motorway opens - the 25-mile M6 north of Birmingham.

Downing Street said Lord Birt's advice to Tony Blair was confidential and stressed Government policy was set out in the 10 year transport plan.

However, that ends in 2011 and Lord Birt was appointed with a brief to think the unthinkable over transport policy.