London Mayor Sadiq Khan has reiterated his opposition to a proposed third runway at Heathrow Airport, citing concerns that expansion plans are based on outdated data and pose risks to the UK's net-zero commitments. Khan's stance, shared with a coalition of London and home counties council leaders, was formally communicated in a joint letter to the Transport Secretary following a government consultation.
The coalition, including leaders from Wandsworth, Richmond, Kingston, Hillingdon, Southwark, Sutton, and Windsor and Maidenhead, urged the government to withdraw its support for the expansion. Khan's office argues that post-pandemic shifts, particularly a decline in business travel, render the original figures supporting the expansion irrelevant. They believe the project is incompatible with legally binding climate change obligations.
Heathrow Airport has refuted claims that expansion contradicts net-zero goals, emphasizing its commitment to a privately funded noise insulation scheme for local residences. The airport stated that its expansion plans include infrastructure improvements, such as widening a section of the M25, and that it will present funded solutions for public transport upgrades during the planning process. Heathrow asserts that the expansion is crucial for national growth, projecting the creation of over 100,000 jobs, a £150 billion boost to British trade, more affordable travel, and revitalization of the UK's steel industry.
The Back Heathrow campaign criticized the councils' opposition, asserting it does not reflect the views of local residents. Executive director Parmjit Dhanda stated that over 100,000 local members support the expansion, highlighting its potential economic benefits and calling the new runway "way overdue."
The Department for Transport acknowledged that it is carefully considering all responses to the consultation before outlining its next steps later this year. A spokesperson affirmed that any expansion would proceed only if it aligns with climate change obligations and adheres to strict environmental standards for air quality and noise pollution. The department previously supported expansion under Prime Minister Keir Starmer's government in 2025.