London Heathrow Airport has unveiled ambitious £49 billion expansion plans that could see it nearly double passenger capacity within a decade through the addition of a third runway and new terminal facilities.
The Capacity Crisis at Britain's Busiest Airport
Heathrow handled 83.9 million passengers in 2024 and is operating dangerously close to its annual limit of 480,000 take-offs and landings. At peak times, aircraft movements occur every 80 seconds, creating significant delays and inefficiencies throughout the aviation network.
Chief Executive Thomas Woldbye describes the airport as "operating at capacity to the detriment of trade and connectivity," emphasising the urgent need for expansion. The current constraints mean inbound aircraft often circle in holding patterns before landing, increasing journey times, noise pollution, fuel consumption and emissions unnecessarily.
Heathrow's Vision: A Third Runway by 2035
The centrepiece of Heathrow's proposal is a 3,500-metre third runway northwest of the existing two runways, requiring the complex relocation of the M25 motorway into a tunnel 130 metres west of its current position. This "shovel-ready" plan, fully privately financed according to the airport, could enable flights to operate from the new runway within ten years.
The expansion would allow Heathrow to increase annual aircraft movements by more than half to 756,000, while passenger numbers could surge by 80% to 150 million passengers each year. Terminal 5 would be significantly expanded, with new satellite facilities and additional car parking proposed north and south of the runways.
Financial Controversy and Competing Proposals
The staggering £49 billion price tag has sparked controversy, with £21 billion allocated for the runway and airfield infrastructure, £12 billion for new terminal capacity, and £15 billion for modernising existing facilities. Airlines have expressed alarm that current passengers might subsidise future expansion through increased charges.
Heathrow faces competition from the Arora Group, which has submitted a cheaper alternative proposal costing approximately £25 billion. Their "Heathrow West" plan features a shorter runway that avoids disrupting the M25, promising faster delivery and reduced environmental impact.
Environmental campaigners and local residents strongly oppose any expansion, citing increased noise, traffic and carbon emissions. The No 3rd Runway Coalition chair Paul McGuinness argues the project represents "the most expensive and least cost-effective airport expansion anywhere in the world."
The Department for Transport is currently evaluating both proposals, with the government aiming for an operational third runway by 2035, though the complex planning process and potential legal challenges could significantly delay this timeline.
