Heathrow has approved new investment to begin work on a planning application for a third runway.

The airport says construction of a third runway would see billions of pounds of private investment flow to businesses in every region of the UK, while increased capacity would boost competition, strengthen airline networks and enhance the UK’s global trading links.

Delivering the project remains complex. The government has set the timetable to secure planning permission by 2029 and bring a third runway into operation in a decade. Heathrow’s shareholders continue to strongly support expansion and the project will only proceed once the necessary regulatory and policy frameworks are firmly in place. Decisions on these key issues are expected throughout 2026.

In spring 2026, clarity is required from the Civil Aviation Authority (CAA) on how early costs can be recovered.

Over the summer, the Department for Transport will publish the draft Airports National Policy Statement (ANPS) and the CAA will decide on the long-term regulatory model which will determine if private investment will be forthcoming.

In the autumn, Parliament will be asked to decide on the final ANPS – a decision which will set the planning framework for the project and put the UK on course for first flights from a third runway in a decade.

Heathrow CEO, Thomas Woldbye, said: “Heathrow expansion is taking another significant step forward today as our Board greenlights starting work on the planning application. This decision means we are on track to secure planning permission by 2029 and reflects Ministers’ renewed commitment to expansion and progress made to speed up delivery of the project to boost UK economic growth.

“Heathrow expansion is a critical national project and a central part of our journey to make Heathrow an extraordinary airport, fit for the future. Maintaining momentum will mean the CAA and Ministers remain focussed on securing the benefits of the project by meeting vital milestones in 2026 that are essential to enabling the next phase of delivery.”

Costain is currently working to deliver asset renewals and construction projects at Heathrow and last month was selected to deliver infrastructure to support a new baggage system at Terminal 2.

Jonathan Willcock, managing director, transportation, at Costain, said: “Today’s announcement signals further positive momentum for an exciting expansion project that will cement the UK’s position as a global hub. Increasing Heathrow’s capacity will support skills development, create jobs and boost trade, all of which are critical in enabling a more economically prosperous and resilient future.

 “We know from working on complex infrastructure projects that the key to success lies in robust, detailed planning. Early contractor involvement and fostering collaboration through long-term partnerships will ensure that the expansion is delivered safely and efficiently to plan.”