‘The economic case stacks up’: UK chancellor renews government backing for Heathrow expansion

Chancellor John Healey has restated the UK government’s backing for the expansion of London Heathrow Airport, insisting that the economic case for a third runway “stacks up” despite continued opposition to the project.

Speaking in the House of Commons, Healey defended the government’s decision to proceed with the long-delayed expansion after Liberal Democrat MP Sarah Olney challenged him over the proposed runway.

Government backs Heathrow after ‘years of indecision’

“After years of delay, years of indecision, years of often vexatious challenge, we have given the go-ahead to this project quite simply because the economic case stacks up and will help bring growth,” Healey said.

His comments reaffirm the government’s position on Heathrow expansion following former Chancellor Rachel Reeves’ decision in January 2025 to back a third runway as part of Labour’s plans to boost economic growth.

Reeves said at the time: “I have always been clear that a third runway at Heathrow would unlock further growth, boost investment, increase exports, and make the UK more open and more connected as part of our Plan for Change.

“And now the case is stronger than ever because our reforms to the economy – like speeding up our planning system, and our strengthened plans to modernise UK airspace – mean the delivery of this project is set up for success.”

Expansion in numbers: £49 billion, 150 million passengers per year

The proposed expansion would add a third runway to Heathrow and increase the airport’s capacity to as many as 756,000 aircraft movements and 150 million passengers a year, according to plans supported by the government.

The wider project is currently estimated to cost around £49 billion, including the runway, terminal expansion and associated infrastructure. 

The cost has become a major point of contention with airlines, which have warned that higher airport charges could ultimately be passed on to passengers.

International Airlines Group, the parent company of British Airways, has called for the cost of the runway scheme to be capped, while Virgin Atlantic has warned over the project’s costs.

The airlines have also called for affordability to be added to the government’s existing tests for the project, alongside its impact on climate change, noise, air quality and economic growth.

Heathrow argues that additional capacity is needed to relieve congestion at the UK’s main hub airport. 

Opposition remains from environmental groups 

While moves to expand to Heathrow have progressed under the Labour government, opposition to the project remains – both politically and from environmental groups. 

London Mayor Sadiq Khan has maintained his opposition to a third runway, arguing that the case for expansion has not been adequately established and that the environmental and infrastructure consequences for London remain serious. 

His latest concerns have focused particularly on aircraft noise, night flights and the impact of increased passenger numbers on the capital’s transport network.

Friends of the Earth takes an even broader view, arguing that Heathrow expansion is fundamentally incompatible with the UK’s climate commitments.

In July 2026, the environmental organisation published an extensive assessment entitled ‘15 reasons why Heathrow airport expansion is wrong.’ It argues that the Government’s own figures do not justify the project economically or environmentally. 

Friends of the Earth estimates that the economic benefit would amount to around £2 billion by 2056 (the equivalent to only 0.05 per cent of GDP) and says this would be outweighed by the project’s social and environmental costs.

The organisation also disputes the argument that Heathrow expansion would spread prosperity throughout Britain. It says at least three-quarters of the projected economic benefit would go to London and the Southeast, while some jobs could simply be displaced from other regions.