Boris Johnson clashes with David Cameron on high-speed rail

The disagreement leaves the Mayor publicly at odds with the Tory leader over three key transport policies: airports in London, Crossrail and now the proposed High Speed 2 link.

Mr Johnson refused to back the official Conservative Party blueprint on the planned line from London to Birmingham, Manchester, and Leeds, which would carry 250mph trains.

Shadow transport secretary Theresa Villiers has stressed that a crucial interchange should be at Heathrow, not at Old Oak Common in west London as the Government has proposed.

Ms Villiers dismissed the Old Oak Common site as "Wormwood Scrubs International", saying it was 10 miles from the airport, was not linked to the Tube, and passengers going to Heathrow would have to change trains.

But Mr Johnson pointedly declined to endorse this criticism, instead saying more research needs to be done. "We must give the utmost consideration to the exact route and where it will stop," he said. "A central London terminal is essential as well as an interchange with Crossrail to the west of London in order to whisk people to and from Heathrow as speedily as possible."

Old Oak Common would also link to Crossrail, the Heathrow Express and the Great Western line. Asked specifically whether the Mayor agreed the Old Oak Common plans were "flawed", the Mayor's Office issued a statement from Kulveer Ranger, his transport adviser.

Mr Ranger said: "He believes thorough research must be carried out before its final location is confirmed. Key to that research should be the location's ability to support passengers heading to and from Heathrow." The Mayor and his party have already been unable to publicly agree policy on Heathrow — the Conservatives are not supporting Mr Johnson's plans for a Thames estuary airport. There are also differences over Crossrail, with the Mayor fully behind the scheme but shadow chancellor George Osborne failing to guarantee funding.

Old Oak Common is also backed by Tory-controlled Hammersmith and Fulham, where the site is located. Mark Loveday, the council's strategy chief, said: "It is unrivalled as a site for west London's High Speed 2 interchange.

"It is perfectly placed to connect the country with Heathrow and will deliver tens of thousands of new jobs and homes to one of the most deprived communities in Britain." He sought to claim the Tories were not against an interchange at Old Oak Common, but Conservative sources said they were.

Local MP Andy Slaughter, Labour member for Ealing, Acton and Shepherd's Bush, said: "I am annoyed by Theresa Villiers's insulting statements about my constituency."

Under the Government's proposals, work on the London-Birmingham section of High Speed 2 would start in 2017 and cost up to £17.4 billion. Journey times between the two cities would fall from 84 minutes to 49 minutes.

The entire project would cost about £30 billion. The line would terminate at a redeveloped Euston station and the Euston Arch could be rebuilt.