A high-speed rail link between London and Scotland that would cut journey times from Birmingham to the capital down to an hour could help boost the economy by £60 billion.
The massive potential benefit to the UK of two improved lines - one going up the east coast, the other up the west - was highlighted in a report from planning and engineering consultants Atkins yesterday. However the links would probably not be operational before 2026, the report said, and that would be too late to solve over-capacity of the West Coast Main Line.
High-speed rail links are one of the options being looked at by the Government in a bid to address the country's transport problems.
Earlier this year rail companies warned England needed a fast line between Birmingham and London because the WCML will soon be full.
Eurostar urged the Government to build high-speed links across the country - starting with a new service between London, Birmingham and Manchester.
But the Atkins report claims building two new lines stretching as far north as Glasgow and Edinburgh would give the best economic benefit.
Atkins calculates the cost of the lines would be about £31 billion, but they would deliver £63 billion worth of economic benefits over the first 60 years. London to Birmingham journey times could come down to just one hour while London to Glasgow could take three hours.
Examples of other journey times include London-Wolverhampton 76 minutes, London-Sheffield 80 minutes, London-Leeds 86 minutes, London-Manchester 74-79 minutes and London-Liverpool 96 minutes.
Atkins claims the lines are necessary as capacity on existing lines could be exhausted quicker than expected - perhaps within a decade.
Virgin Trains has already told Ministers it expects severe overcrowding to be a fact of life on the West Coast Main Line as soon as 2011.
It maintains the Government has failed to grasp the urgency of the problem.
Atkins' transport planning managing director Andy Southern said: "The economic gain of a high-speed rail network could be extremely significant."