MPs will vote tonight on £14bn plans for a third Heathrow runway

MPs are set to weigh in on what some have called ‘the biggest transport decision in a generation’ – as political parties look set to expose their divisions.

The spotlight will be on the whereabouts Boris Johnson, who once said he would lie down in front of bulldozers to prevent construction of the £14bn runway.

Mr Johnson, a long-term critic of a third runway, was challenged on Sunday by a Tory colleague to ‘put his money where his mouth is’ and resign as foreign secretary over his opposition to the scheme.

Senior backbencher Sarah Wollaston said that Theresa May’s decision to allow him to avoid her three-line whip in support of the Heathrow plan by going abroad ‘won’t wash’ and called on him to make a ‘principled decision’ to stand down.

Meanwhile, former whip Stephen Crabb told BBC Radio 4’s Westminster Hour that Mr Johnson would ‘need to look his constituents in the eye and explain where he was on the night of the Heathrow vote’.

In a night set to divide British politicians, more than 40 Labour members said they would go against party policy and support the government’s decision.

Labour is officially opposed to the expansion but Jeremy Corbyn has allowed his MPs a free vote on a measure that is supported by trade unions but opposed by the shadow chancellor John McDonnell.

On the eve of the vote, transport secretary Chris 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 added: ‘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.’

Ahead of the vote, officials said the expansion of Heathrow would create 114,000 extra jobs in the area around the airport by 2030, with an extra 16m long-haul seats by 2040.

It would represent the first full-length runway in the south east since the Second World War, the Department for Transport said.

Mr Grayling outlined five pledges over the Heathrow expansion:

n No cost to taxpayers.

n An economic boost providing 100,000 jobs.

n Guaranteed benefits for the whole country including internal flights, rail links and ‘global opportunities’ for regional firms.

n Built-in environmental protections.

n The ability to fine Heathrow or ground aircraft if Heathrow breaks its own promises over the scheme.

Speaking to the Westminster Hour on Sunday, Totnes MP Dr Wollaston pointed out that Greg Hands last week resigned as international trade minister to vote against the Heathrow whip.

She said: ‘I think this would be an opportunity for a colleague like Boris Johnson to actually put his money where his mouth is.’

The resignation of Chelsea and Fulham MP Mr Hands put pressure on Mr Johnson, but Mrs May last week confirmed he would miss the vote by being ‘the living embodiment of global Britain’ abroad.

The government has so far declined to say where Mr Johnson will be on security grounds.

On Sunday night Mr Hands, who went to Romania after stepping down, tweeted: ‘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.’

The number of opposition MPs prepared to vote for Heathrow suggests the Commons vote on Monday night should pass with some ease.

Those who have signed the letter include many leadership critics, including Luciana Berger, John Mann, Mike Gapes and Wes Streeting, who argue it is right ‘in principle’ to back a scheme that will create 180,000 jobs.

But the scheme has its critics, including Paul McGuinness, chairman of the No 3rd Runway Coalition.

He said: ‘Heathrow expansion will be bad for London and bad for Britain.

‘Bad for London, because of all the extra pollution and noise, and the large call on the public purse to upgrade already congested rails and roads.

‘And bad for Britain because it’s yet another South East-centric scheme that will suck activity from the regions and further entrench the geographical economic divide in our country.’