The proposals would see a new junction created between Langley and Iver stations, linking with a 5km tunnel for trains to access Heathrow Terminal 5.

If planning permission is granted, Network Rail would begin initial highways enabling work at the end of 2016, with tunnel enabling work starting in early 2018. The project would be complete in 2021.

Network Rail met with MPs and other local stakeholders yesterday to discuss the detailed plans, known as the Western Rail Access Programme.

Patrick Hallgate, Network Rail route managing director Western route, said: “Our plans for a new rail link to Heathrow from the west will dramatically improving rail links, reduce congestion on existing rail services and provide a boost to the local economy.

“It’s important that we take the opportunity to discuss these plans so we can ensure the investment made in a bigger, better railway delivers maximum benefit.

“We will need to secure a Development Consent Order to deliver the Western Rail Access Programme.

“A steering group of industry leaders, from organisations including Network Rail, Department for Transport, Thames Valley Berkshire LEP, Slough Borough Council and Heathrow Airport, is working together to progress the proposals.”

The project would be complete in 2021.