A £12bn high-speed rail line to link the North-East to London must be the country's top transport priority, the Liberal Democrats said yesterday.

The party said the line, which would reduce the London-Edinburgh journey time to three hours, could be built within a decade.

It would ease pressure on the "near-bursting" East Coast Main Line, which would allow more local and regional train services, the LibDems said.

And they urged the Government to look to the example of the high-speed Paris-Lyon route, which paid for itself in only 15 years.

John Thurso, the party's transport spokesman, told the conference in Bournemouth: "High speed rail is an efficient means of transport in itself. But it also delivers extra capacity for local trains and freight and a realistic alternative to short-haul, domestic travel.

"It is vital that we commit to this project before congestion brings Britain to a standstill."

It is the first time a major party has committed itself to building a North-South rail link, which was proposed by the Strategic Rail Authority two years ago.

The LibDems said 140mph trains would run from London to Edinburgh up the east coast, only stopping at Birmingham, Leeds and Newcastle.

Future expansion would allow top-speed services to reach other major cities, including Liverpool, Manchester, Sheffield and Glasgow.

Mr Thurso insisted the project could be afforded by using a mix of private finance, a bond scheme and a land value tax on businesses that would benefit from construction.

Direct government funding would come from savings brought in by scrapping plans to upgrade the existing East Coast Main Line, he said.

Because construction would probably not begin until 2010, only modest expenditure would be needed during the next Parliament.

Mr Thurso said the bill of between £10bn and £12bn was only slightly more than the cost of improving the West Coast Main Line, which was between £8bn and 9bn.

The scheme was the centrepiece of a 30-year strategy, unveiled yesterday, which included national road user charging to replace vehicle excise duty and fuel tax.

Motorists would pay more to use busy main roads at peak periods and less to use routes in remote areas.

The transport strategy also called for more car sharing, transferring freight to rail and ensuring the full cost of aviation pollution was borne by the industry.

l Safety inspectors produced a positive report on the state of Britain's railways yesterday despite an increase in the deaths of railway employees.

But the annual report from the Health and Safety Executive noted that nine railway employees had lost their lives, three more than the previous year.

But there were no train crash deaths during the year, the first time since 1998-1999.

The report covered the period from April 1, last year, to March 31, this year