Gordon Brown will attempt to use plans for a £30bn high-speed rail line as a vote winner at the next election but pledges to introduce the new services also create an electoral headache for both the Government and the Conservatives.
Labour MPs representing constituencies in London that will be hit by the project began voicing concerns yesterday. Frank Dobson, the former Health Secretary who represents the north London seat of King's Cross, said the inevitable expansion of Euston station would have a profound effect on his constituents. The project will not help the cause of some Labour MPs trying to hang on to their seats. The ultra-marginal seat of Warwick and Leamington, where Labour MP James Plaskitt limped home to victory in 2005 with a majority of less than 300 votes, will be affected.
However, Labour strategists believe the plan by Lord Adonis will boost the party's fortunes overall. As well as a manifesto pledge to build the new route, it has been enthusiastically adopted by Mr Brown, who has incorporated the plans into his "core script" for the election campaign.
The advent of high-speed rail presents a difficult challenge for the Tories, who will have to upset many of their own supporters in realising their vision for a high-speed network. The line needs to be as straight as possible to maximise time savings, therefore passing through Tory heartlands in the South-east.
Theresa Villiers, the shadow Transport Secretary, refused an early glimpse of Lord Adonis's plans, partly because she did not want to be seen by Tory voters as being part of a cosy Westminster club not listening to their concerns.
Several Tory-controlled councils are eager to see the project go ahead and want Ms Villiers to co-operate. She faces a difficult balancing act.