Revealed: How the M25 would be moved under Heathrow Airport's plans for a third runway

Heathrow chiefs have laid out how they believe the M25 can be moved without creating traffic chaos under plans for a third runway.

They say that a new section would be built away from London’s orbital motorway and once completed traffic would then switch over through “carefully planned overnight closures”.

However, many Londoners are likely to be sceptical about the claims, particularly given the lengthy disruption caused by improvements at Junction 10 of the M25 where it meets the A3 in Surrey.

The Government has already said it will support a third runway at Heathrow as part of its plans to get the British economy growing again (Jonathan Brady/PA)

PA Archive

Sir Keir Starmer’s administration had supported a third runway as his Chancellor Rachel Reeves scrambled to find ways to boost the UK’s economic growth while hitting businesses with tax rises.

The expansion scheme, which is already estimated to cost £49 billion with terminal and other improvements, is believed to have been hit with years of delays.

Lord Sadiq Khan opposes a bigger Heathrow

PA

“The answer is surprisingly simple: Build the new section of the M25 away from the existing motorway, then switch traffic across when it's ready,” it said ahead of the airport’s chief executive Thomas Woldbye appearing before the Commons transport committee to explain the expansion blueprint.

“Heathrow's plans would see a brand-new tunnel and bridges constructed 130 metres west of the current M25, allowing most of the work to happen offline and separate from day-to-day traffic.

“Rather than years of major disruption, traffic would transfer to the new route through carefully planned overnight closures.”

It stressed the upgrade to the motorway would be privately-financed.

The airport bosses added that they had explored other options such as building over the M4 spur.

But they concluded that this would require significantly more demolition in local communities, and create greater disruption for road and rail users during construction.

They also argued: “Building airport infrastructure over major roads has already been successfully delivered at airports including Frankfurt and Paris Charles de Gaulle.”

Heathrow claims a third runway would unlock more than 100,000 jobs and £33 billion of private investment across the UK.

However, MPs who oppose the expansion say the economic benefits would be limited, citing Government figures.