The 200mph lines, one for each side of the country, would cut two hours off the journey time between London and Edinburgh and allow people to commute from Birmingham to London in 45 minutes. The lines could be paid for by introducing tolls on motorways. Greengauge 21, a campaign group that includes senior rail industry figures, published plans for the network yesterday.

Network Rail, which owns the existing network, has appointed a team of officials to study the concept, but Greengauge 21 fears that the project is progressing too slowly.

The group's high-speed rail manifesto argues that high-speed rail is essential to close the income and productivity gap between the South East and the North.