Heathrow Airport has a secret underneath it: A huge, ghost railway station built to serve Terminal 5.

The empty station, which was completed in 2008, already has platforms but track and signals would need to be installed to make it operational.

Giving BBC Radio 5 live an exclusive tour, Heathrow's head of surface access Chris Joyce said: “The scale is absolutely immense.

“For me, this is the biggest kept secret at Heathrow.”

This clip is from Stephen Nolan: Inside Heathrow - broadcast on Radio 5 Live at 21:00 GMT on Saturday 20th February.