MPs will decide later whether to expand Heathrow airport in a crunch vote which looks set to expose divisions in both Labour and Tory ranks.
Transport Secretary Chris Grayling said it was “the biggest transport decision in a generation” as he called for cross-party support to approve a third runway.
The spotlight will be on the whereabouts of Boris Johnson, who once threatened to lie down in front of the bulldozers if a third runway got the go-ahead at the west London airport.
Image: (L-R) Chris Grayling and Boris Johnson
The foreign secretary is set to miss the vote because he is abroad, but the government has so far declined to say where he will be on security grounds.
Mr Johnson broke cover to tell the Evening Standard: “My resignation would have achieved absolutely nothing.”
Senior Tory backbencher Sarah Wollaston has called on him to take the “principled decision” and resign in order to vote against expanding Heathrow.
She said the prime minister’s decision to allow Mr Johnson – who is MP for Uxbridge and South Ruislip in west London – to avoid a three-line whip in support of the Heathrow plan by going abroad “won’t wash”.
“I think this would be an opportunity for a colleague like Boris Johnson to actually put his money where his mouth is,” Dr Wollaston said.
Greg Hands, who resigned as international trade minister in opposition to the third runway, appeared to mock Mr Johnson’s absence on the eve of the vote.
Image: Greg Hands resigned as as international trade minister over Heathrow
Mr Hands tweeted on Sunday: “Great to arrive back in the UK at Luton Airport in time for the match today and to vote against #Heathrow expansion tomorrow. I wouldn’t want to be abroad for either of those. #commitments.”
Mr Grayling admitted to Sky News on Monday he “didn’t know where” Mr Johnson was.
He said: “The prime minister has been very clear that there are parliamentary colleagues who have longstanding views about this, perhaps for constituency reasons who need to take their own decisions about how they approach it.
“We all fought a general election on the manifesto of expanding Heathrow Airport.
“But equally, where there are people who have got particularly constituency issues, we’ve left them the freedom to carry on expressing the views they’ve always had.”
Video: Grayling: ‘I don’t know where Boris Johnson is’
Theresa May confirmed last week that Mr Johnson would miss the vote on Heathrow, describing him as “the living embodiment of global Britain” abroad.
The Conservative row came as more than 40 Labour MPs said they would go against party policy and support the government’s decision.
The group whose constituencies span the country put their names to a letter to colleagues in the party urging them to support a project they say could create 180,000 jobs across the UK.
Labour is officially opposed to the expansion but Jeremy Corbyn has allowed MPs a free vote on a measure that is supported by trade unions.
Image: MPs will vote on whether to build a third runway at Heathrow
Mr Grayling said that “thousands of new jobs and the country’s ability to compete on an international stage and win new global trade” were at stake.
He said: “I hope colleagues from across the House will now put aside party and political differences to take a decision in the long-term national interest.”
Officials say the expansion of Heathrow would create 114,000 extra jobs in the area around the airport by 2030, with an extra 16 million long-haul seats by 2040.
More from Heathrow Airport
It would also represent the first new full-length runway in the south east since the Second World War, the Department for Transport said.
But opponents have attacked the scheme on environmental, noise and financial grounds grounds, with Friends of the Earth saying it was “morally reprehensible” and would see the enlarged Heathrow emitting as much carbon as the whole of Portugal.