City Hall Liberal Democrats warn the mayor to ‘be careful not to appear to backtrack on promises he has made to Londoners’
London Mayor Sir Sadiq Khan has faced criticism after failing to allocate funding in his latest budget for a potential legal challenge against Heathrow Airport’s expansion. The omission has sparked frustration among members of the London Assembly, including figures from his own Labour Party, who argue that he should take firmer action against the proposed third runway.
Budget fails to address Heathrow expansion opposition
The London Assembly passed a motion last week urging the mayor to earmark funds for legal action should the Government move forward with Heathrow’s expansion plans. The motion, led by the Liberal Democrats, called on Sir Sadiq to “make clear in his final draft budget 2025/26… that funding is available for legal action against the Government if expansion plans are pursued.”
Despite the mayor’s repeated assertions that he remains opposed to a third runway at the UK’s busiest airport, his budget—published late on Monday evening—made no mention of Heathrow or provisions for a legal fight.
Mayor’s office defends position
A spokesperson for Sir Sadiq defended the mayor’s approach, stating:
“The mayor has been clear that he remains opposed to a new runway at Heathrow Airport because of the severe impact it will have on noise, air pollution and meeting our climate change targets.
“He will scrutinise carefully any new proposals that come forward from Heathrow. Only after any new proposals come forward can any next steps be decided.”
The response, however, has not satisfied critics who fear that by not committing funds in advance, the mayor is signalling a reluctance to act decisively.
Assembly members express frustration
Gareth Roberts, the Liberal Democrat assembly member who proposed the motion, expressed disappointment at Sir Sadiq’s decision. Mr Roberts, who also leads Richmond-upon-Thames Council, said:
“It is deeply disappointing that the mayor has not ringfenced funding in his final draft budget to support legal action against Heathrow expansion.
“He must take the threat of increased noise and air pollution as seriously as possible and give reassurance to Londoners that he is ready to fight against it in court if necessary. He should be careful not to appear to backtrack on promises he has made to Londoners while he waits to see Heathrow’s plans.”
Green Party assembly member Zack Polanski seconded the motion, which was also supported by both Labour and Conservative members of the Assembly.
Divided opinions on Heathrow expansion
While opposition to the third runway remains strong among many Londoners and political figures, the expansion has also found its defenders. Reform UK’s sole assembly member, Alex Wilson, dismissed the concerns raised by other Assembly members, calling Heathrow’s expansion “superb news” for London and the wider UK economy.
Mr Wilson argued that a third runway would bring “more jobs, more money and less net zero” and described it as “a crucial piece of infrastructure for London, but also for the country as a whole.”
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Heathrow’s CEO targets third runway by 2034
The debate over Heathrow expansion gained renewed attention last month when Chancellor Rachel Reeves confirmed the Government’s in-principle support for the project as part of wider economic growth efforts.
Heathrow Airport chief executive Thomas Woldbye recently stated that he wants planes to take off from a third runway before the end of the next parliament, which must conclude no later than 2034.
While the expansion will be funded with private investment, the Government’s approval is contingent on meeting environmental and climate targets. Ms Reeves has invited Heathrow to submit formal plans by the end of summer 2025, making it clear that they must align with “legal environmental and climate objectives” before receiving Government backing.
What happens next?
With Heathrow’s expansion plans now firmly back on the political agenda, pressure will likely continue to mount on Sir Sadiq to take a clearer stance on legal opposition. Environmental groups and local campaigners are expected to demand stronger commitments from City Hall, while political opponents may use the issue to challenge the mayor’s credibility on climate and pollution policies.
As Heathrow prepares to finalise its proposals, Londoners will be watching closely to see whether Sir Sadiq takes a stronger stance—or whether his omission from the budget signals a softening of his position.
