Heathrow third runway opposed by London mayor over £9bn transport costs
Sadiq Khan and TfL warn expansion would add 60,000 daily car trips and halve noise respite for residents
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Headline overstates mayor's direct opposition to expansion risk.
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The London mayor and Transport for London have formally opposed Heathrow Airport’s plans for a third runway, warning the expansion would add 60,000 daily car trips to roads around the airport and cost £9bn in unfunded transport upgrades. The joint response to the government’s consultation argues the proposals are incompatible with climate targets and rely on outdated evidence.
Sadiq Khan said the expansion posed a risk that London could not afford. In a statement reported by the BBC, he said, "The evidence suggests Heathrow expansion is a risk that we simply cannot afford to take." The mayor’s office added that additional flights could reverse progress in reducing air pollution near the airport, particularly in areas affected by the Ultra Low Emission Zone.
Heathrow officer uses bird sounds to deter wildlife from runways
Jack Quantick-Thorne, an airfield operations officer, employs a range of recorded bird calls to manage wildlife on the tarmac.
Transport and noise impacts
TfL’s submission to the consultation highlights several concerns. The authority estimates the expansion would generate 22 million additional road journeys annually on the M4 and M25. It also warns that predictable noise respite periods for residents would drop from 50% to 25% of the day due to a projected 58% increase in flights.
The £9bn surface access cost includes upgrades to the Elizabeth and Piccadilly lines, as well as new southern and western rail links. TfL said no funding agreement exists for these projects. Heathrow Airport Limited has stated it will present "viable and funded solutions" for public transport upgrades as part of the planning process, as reported by the BBC.
Westminster Council demands Oxford Street impact study
The council is concerned about displaced traffic affecting surrounding neighbourhoods and residents' health.
Jobs and economic claims
Heathrow Airport Limited has defended the expansion, claiming it would unlock 100,000 jobs and £150bn in trade benefits. A spokesperson told the BBC the project was "the most important economic growth opportunity available to the UK." The airport also said it was committed to a privately funded noise insulation scheme for local homes.
The Back Heathrow campaign, which supports the expansion, said more than 100,000 local members backed the plans. Executive director Parmjit Dhanda said the project was "way overdue" and would deliver jobs and economic growth. However, a coalition of London and home counties councils, including Hillingdon, Richmond and Windsor and Maidenhead, has urged the government to withdraw support for the third runway.
The whole case for Heathrow expansion relies on outdated evidence that fails to take into account the urgent challenges we face today.
Sadiq Khan, London mayor
Government review underway
The Department for Transport said it would "carefully consider all responses" before setting out next steps later in 2026. A spokesperson told the BBC the government remained committed to expansion but only if it met legally binding climate obligations and strict environmental rules on air quality and noise. The final decision will follow a parliamentary vote in 2029.
TfL has argued the expansion’s modelling is outdated, citing post-pandemic changes in travel habits and a decline in business travel. The authority said the figures used to support the project are over a decade old. The mayor’s opposition sets up a potential conflict with pro-expansion groups, including some within his own party.
Questions this report answers
+How many extra car trips would Heathrow expansion cause?
TfL estimates the expansion would generate 60,000 additional daily car trips, adding 22 million road journeys annually to the M4 and M25. This would increase congestion and air pollution in surrounding areas, including parts of Barnet.
+What would the transport upgrades cost?
TfL estimates the expansion would require £9bn in surface access upgrades, including improvements to the Elizabeth and Piccadilly lines and new rail links. No funding agreement for these projects currently exists.
+What happens next in the Heathrow expansion process?
The Department for Transport will review all consultation responses before announcing next steps later in 2026. A final decision on the third runway will follow a parliamentary vote in 2029.
+Which councils oppose the Heathrow expansion?
A coalition of London and home counties councils, including Hillingdon, Richmond, Kingston, Wandsworth and Windsor and Maidenhead, has urged the government to withdraw support for the third runway. They argue the plans are incompatible with environmental targets.
WE FILE
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The London Travel Desk assembled this report from the outlets listed below. Language-model drafting is reviewed under human editorial supervision, with scoring notes and corrections kept visible.
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