Heathrow’s third runway expansion may be built over several phases in a bid to hit the government’s ambitious timeline, opening the door to a proposal tabled by rival bidder Heathrow West.

In planning documents published by the Department for Transport on Thursday, the government said that a phased construction of the mega-project may be necessary given the scheme’s “scale, complexity and delivery timeframe”.

Heathrow West, backed-by billionaire hospitality tycoon Surinder Arora, tabled its initial bid to develop the third runway last year, challenging a proposal put forward by Heathrow Airport Limited, the owner and operator of Heathrow Airport.

“A phased scheme which enables, and does not hinder, the delivery of the completed scheme as a whole is capable of being compliant with this national policy statement (NPS),” the department said. “Where a phased approach is proposed, the application should clearly identify the content and sequencing of each phase, including how runway, terminal and other supporting infrastructure will be coordinated and integrated over time.”

The development is the first sign that ministers might entertain a third runway proposal that includes tackling the multi-billion-pound expansion in several stages, just weeks after two major airlines threw their weight behind the two-phase approach to the development.

The two-phased proposal first emerged in May and suggests first building a new terminal and a shorter, 2,800m runway which would avoid re-routing the M25. Heathrow West would then extend the runway to its full 3,500m length and reroute the motorway that surrounds Greater London should ministers still wish to proceed with the wider expansion.

Both Virgin Atlantic and British Airways owner IAG have come out in support of the multi-stage expansion, which Heathrow West argues is the only way for the megaproject to be operational before Keir Starmer’s ambitious 2035 deadline. The developer pivoted to a two-phased approach, having lost with its original proposal, which only included plans for a shorter 2,800m strip.

Ministers’ acknowledgement of the phased approach’s potential benefit keeps alive the prospect of a rival developer overseeing the development and operations for the first time in Heathrow’s history. Last month, the aviation watchdog ruled for the first time that alternative developers can bid for and run the west London hub’s infrastructure

The development was included in an eagerly anticipated planning document laying out the ground rules for a successful third runway expansion and takes the country one step closer to what promises to be one of the UK’s most ambitious infrastructure projects in modern British history.

Heathrow hails ‘critical step’

Transport minister Heidi Alexander said the publication of the document – known as the national policy statement – was a “signal on the importance the government places on the need for expansion”.

She also designated Heathrow’s expansion as “critical national growth infrastructure”, meaning it can bypass thorny local planning laws should ministers deem them to come into conflict with the national interest.

Heathrow Airport Limited chief executive Thomas Woldbye said: “We strongly welcome that the government has taken this next critical step.

“The UK cannot realise its full economic potential without an expanded Heathrow and this is an important step towards delivering the capacity the country needs.

“Our plan is privately funded by some of the largest investors in the world, widely supported by businesses, trade unions and communities across the country, and it’s ready to go after years of scrutiny.”

Alongside the planning document, ministers launched a 10-week consultation in which businesses and households can respond to the draft policy statement. Once complete, the rival developers will then pull together proposals based on the criteria laid out in the final planning document.

Surinder Arora said: “We welcome the government progressing Heathrow expansion. We specifically welcome them leaving the door open to competitive tenders to ensure the best proposals can be advanced.

“This is in addition to making allowances for a runway of up to 3,500m, which makes the scheme more flexible in order to deliver benefits in timescale and affordability.”