Plans for a new railway connecting Surrey to Heathrow and beyond have resurfaced as the track’s backers welcomed government support for a third runway at the airport.

The line, called the Heathrow Southern Railway (HSR), is a privately financed proposal to link towns in Surrey to one of the world’s busiest airports.

If built, it would operate between Heathrow and London Waterloo via Staines. There would also be direct trains from the airport to Woking and Guildford, before carrying on to the south coast.

Heathrow shown with a third runway over the M25
Heathrow shown with a third runway over the M25 (Heathrow)

Heathrow Southern Railway said it also would provide for an extension of the Elizabeth Line to Staines.

Baroness Jo Valentine, the group’s chairperson, said: “The UK Government has set a bold agenda for growth with its support for a third runway at Heathrow Airport. Our railway enhances that growth by increasing connectivity and reducing surface emissions.

“These benefits accrue with a two runway airport but will be enhanced with an additional runway. We look forward to working with all partners to make this a reality.”

Mark Livock, chief executive, added: “The new government has expressed interest in finding ways to harness private sector finance in making the delivery of major infrastructure schemes more affordable.

“Heathrow Southern Railway has a depth of experience in creating opportunities for private investment that could deliver tangible benefits to the UK, and southern rail access to Heathrow would positively transform public transport connectivity to Europe’s busiest airport.”

The group estimates that the new route would cut millions of road journeys – with many of those from motorists using the M25.

An HSR spokesperson said: “Our proposed route starts at Heathrow’s Terminal 5 station and is intended to run mainly in tunnels and be electrified to minimise environmental impact.

“It rises to the surface to connect to the existing railway near Staines and Virginia Water.”

Currently, passengers travelling from some Surrey towns to Heathrow must transfer at Woking or Guildford stations from train to a bus service to reach the airport.