Heathrow Airport in London wants to expand for 49 billion pounds, or more than 56 billion euros. The plan includes the construction of a controversial third runway of 3,5 kilometers, which is expected to cost at least 24 billion euros.
A new terminal will also have to be built, current facilities will have to be renovated, and London’s ring road will have to be rerouted.
Heathrow has been wanting to build a new runway for some time, but it has now formally submitted its “shovel-ready” proposal for a new 3.5-kilometer northwestern runway to the British government.
Tunnel under the new runway
The runway would cross the M25 motorway, which Heathrow plans to reroute through a new tunnel under the new runway, constructed offline and switched in “overnight” to limit disruption.
If the plans go ahead, it could be ready within 10 years. However, this would require the demolition of no fewer than 752 homes in the surrounding area.
In addition, a new T5X terminal complex would be built, Terminal 2 would be expanded, three new satellite terminals would be added, and Terminal 3 would be closed. Train, bus, and bicycle connections to the airport would also be improved.
276,000 additional flights per year
According to Heathrow Airport, the expansion of the airport will make room for 276,000 additional flights per year, bringing the total to 756,000 flights, and an increase from 82 million annual visitors to 150 million. It would also unlock at least 30 new destinations and increase cargo capacity by 50%.
The additional runway and infrastructure works would create around 100,000 new jobs.
The costs of the works would be 100% privately financed, with Heathrow seeking regulatory framework assurances and the ability to recoup investment via airline fees. The total investment would therefore amount to 49 billion pounds: 21 billion pounds for the runway and airport, 12 billion pounds for the terminal capacity, and 15 billion pounds for the modernization of the current infrastructure.
If everything goes according to plan, the building permit would be ready in 2029. The works themselves would take until around 2035. Expansion is supported by Chambers of Commerce across the UK, trade unions, businesses, and regional airports.
Extra noise and air pollution
The mayor of London, Sadiq Khan, opposes the new runway due to noise pollution, air pollution, and climate goals. According to estimates, the expansion will lead to more than 700 additional flights per day. Heathrow’s annual CO2 emissions could therefore increase by approximately 3 to 5 million tons.
There is also strong opposition to the plans from various environmental associations and residents. The additional flights will expose tens of thousands of extra households to aircraft nuisance. Areas such as Richmond, Hounslow, Windsor, and parts of West London, socially and economically very mixed, will be particularly affected.
More traffic from both planes and cars also means an increase in NO2 and particulate matter, while some areas around Heathrow already exceed WHO air quality guidelines. Opponents also point out that the environmental and financial risks would cause the costs to rise beyond previous estimates. In addition, green heritage sites, wetlands, and agricultural land would be lost.
The British cabinet is said to support the plans. It expressed its support in principle, most recently reaffirmed in early 2025, but it has not yet granted official go-ahead for construction to begin. The British government is expected to make a final decision on the expansion in the fall.
