Will London's MPs have a change of heart over third runway?

Climate protestors urged Labour to vote against a third runway when it was last voted on in 2018

Reviving plans for a third runway at Heathrow has set off another round of soul-searching among London's MPs.

Economics vs environment. Principle vs personal ambition. Choices for some are unlikely to be easy.

When MPs last voted on this in 2018, nearly 30 Labour MPs opposed expansion in a free vote. A handful of those now find themselves not just in government but holding ministerial office.

Many will watch closely for the lead taken by the Prime Minister Sir Keir Starmer – the formulation he finds to explain his change of mind from nearly seven years ago when he voted against.

The decision on whether to back Heathrow's runway expansion goes ahead does not require a vote by MPs in the House of Commons but constituents may want to know where they now stand.

Others in the cabinet who previously objected are Streatham and Croydon North MP Steve Reed, now environment secretary, and Ellie Reeves, MP for Lewisham West and minister without portfolio.

But on the face of it the predicament does not get more complex than for Sarah Jones, who represents Croydon Central.

With a split portfolio - as a minister in both the Department for Energy Security & Net Zero and the Department for Trade, she will be seeking reconciliation within her own job.

Ms Jones is among a number of London MPs including ministers we have been unable to reach to establish their position.

Environment Secretary Steve Reed is among the top team in government who previously opposed expansion

Others in government who opposed the expansion last time around include housing minister Matthew Pennycock, Catherine West, a foreign office minister and Fleur Anderson in the Northern Ireland Office.

For some of senior rank, consistency should come easily.

Foreign Secretary David Lammy and Health Secretary Wes Streeting both supported Heathrow expansion before.

So did ministers Stephen Timms and Seema Malhotra whose Feltham and Heston seat has many constituents where livelihoods are dependent on the airport.

It is still difficult to gauge where many of the new intake of London Labour MPs stand on this – and who might make a stand in future.

In Parliament, Deidre Costigan, MP for Southall, summed up the central difficulty and the potential trade-offs, asking the government to ensure it balanced "the need for growth and good-quality local jobs against the need to minimise both air and noise pollution".

Some MPs will be forced to choose between demands from the government or constituents

With Dan Tomlinson, Joe Powell, Rachel Blake and Danny Beales, you have a quartet of new MPs who have joined the Labour growth group, which has indicated support for the principle of expansion.

Mr Beales won the seat of Uxbridge and South Ruislip whose constituents benefit from the jobs and business generated by the airport but where there is vocal concern about more flights and noise.

He says he will judge any application from Heathrow Airport on the basis that it needs to meet tests on air quality, noise, climate impact and growth, and insists he will not support it otherwise.

Senior Labour figures like Andy Slaughter and Clive Efford look as if it will be hard for them to shift their previous opposition. Diane Abbott and Dawn Butler too.

John McDonnell, currently with the whip suspended and sitting as an independent, has made his continued resistance explicit.

Another staunch opponent up to now is Ruth Cadbury, MP for Brentford and Isleworth, who has recently become chair of the Transport Select Committee.

Sir Sadiq Khan, who was the MP for Tooting before becoming London mayor in 2016, also opposes a third runway. He told BBC Radio London earlier that noise, air pollution and climate change targets were his main concerns.

He said: "We have in London made huge progress in cleaning up our air – still one of the most polluted parts of London with air pollution is around Heathrow.

"Not withstanding my support for growth, I do not support a new runway in Heathrow."

The Conservatives opposed expansion in 2010, pressured by then London mayor Boris Johnson.

They changed tack and proposed a third runway under Theresa May when Mr Johnson avoided the parliamentary vote – overwhelmingly in favour – by flying to Afghanistan.

Now the Tories are set to back the third runway in principle but shadow transport minister Gareth Bacon said there were major difficulties ahead including the rerouting of the M25, the demolition of thousands of homes, nearly a million people under a new flightpath, and the demolition of an incinerator.

All six Liberal Democrat MPs in London say they will oppose any expansion.