Did the prospects of progress after the general election on both HS2 and the new third runway at Heathrow just get a little dimmer?

Boris Johnson, the prime minister, sounded a note of caution about both projects, in the course of an interview yesterday with LBC radio.

Johnson has long been associated with objections to the Heathrow runway and promised to lie down in front of bulldozers to prevent it. As for HS2, one of his first acts as prime minister was to order a review into the viability and cost-effectiveness of the project. The Oakervee review was due to be published in the autumn but has been shelved until after the election.

Johnson told LBC that the £100B cost of HS2 was an "awful lot of money".

The growing belief among close observers of the project is that HS2 will be reconfigured to place a Transpennine high-speed link from Manchester to Leeds at the centre of the project.

The prime minister's comments on Heathrow's new runway left less room for a sympathetic interpretation. Talking to LBC he pointed out that this was a private sector project that had yet to satisfy the rules on air and noise pollution, City A.M. reported.

How far a Conservative government chooses to support either Heathrow runway three, or HS2, will depend on the size, or existence, of its majority. The smaller the majority, the more likely it is that vociferous opponents of the schemes sitting on the Conservative benches can exercise effective leverage.