Heathrow airport expansion: 2025 proposals

In January 2025 the government said it would support proposals for a third runway at Heathrow airport. The Chancellor of the Exchequer, Rachel Reeves, said:

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.

The government invited proposals for a third runway “by the summer”, noting that any expansion must be delivered “in line with the UK’s legal, climate, and environmental obligations”.

Heathrow Airport Limited (HAL), the company that operates the airport, has said that it will share its proposals for a third runway with the government by summer, and has the aim of securing planning permission before the end of this Parliament.

HAL has told the BBC that a third runway at Heathrow could mean an increase from 75 million passengers per annum (mppa) to around 140 mppa. It is not yet clear what the impact may be in terms of additional greenhouse gas emissions, noise and air pollution.

Planning process

A project as big as Heathrow expansion would need to follow the planning process for a nationally significant infrastructure project (NSIP). This means that instead of being determined by a local planning authority, planning permissions would be granted by central government, via a development consent order. This would ultimately need to be determined by the Secretary of State for Transport, following examination by the government’s Planning Inspectorate.

For certain types of national infrastructure development there are National Policy Statements (NPSs) in place. An NPS sets out the policy rationale and ‘need’ for a development and the criteria that the relevant Secretary of State uses to asses an application for a development consent order.

For Heathrow, there is such an NPS: the Airport National Policy Statement, which was designated as government policy in 2018 following a vote in the House of Commons. This gave provisional support for a new north-west runway at Heathrow.

Parliamentary involvement

The government has said the Airports NPS will be reviewed “at speed” if and when it receives new expansion proposals, and that it is possible that the Airports NPS might need to be amended if any proposals are substantially different from those envisaged in 2018.

If the Airports NPS is amended, it will undergo public consultation and parliamentary scrutiny by a select committee before being ‘designated’ as policy, like any other new or amended NPS. The government would not be obliged to schedule a debate in Parliament and there is no automatic requirement for a parliamentary vote.

Reaction to announcement

Airlines UK, the trade body for UK registered airlines, welcomed the government’s announcement on Heathrow expansion. The Leader of the Opposition, Kemi Badenoch, has said she would support expansion, as have a range of business groups and sections of the travel industry.

Environmental groups such as Friends of the Earth and the climate charity Possible said they opposed expansion as it would further contribute to climate change. The government has said that, according to its analysis, it can achieve net zero aviation by 2050 without intervening to limit airport expansion.

Some airlines and Heathrow-based businesses have expressed concern that HAL already charges them high fees (including landing charges and fees for parking and access to utilities) and that the costs of building a new runway will mean these fees may rise and be passed onto passengers and customers.

Further information

Further background on previous plans to expand Heathrow can be found in the Library briefings on Heathrow Airport (2018) and Expansion of Heathrow Airport (2009).

Further information on UK Government plans to reduce aviation's contribution to climate change can be found in the Library briefing on Aviation and climate change (2025)