Secrets of the London Underground Episode Rating Graph

Have a night-time track walk exploring long forgotten stations on the District line in Whitechapel. And they discover how sprawling Oxford Circus was first built.

Tim and Siddy explore the tube station with the most platforms, Baker Street. Siddy visits the disused Edgware Road Signal Cabin with its very last operator.

Explore the disused parts of Piccadilly Circus, the grandest station on the London Underground. And they also visit the long-abandoned Highgate surface station.

Tim and Siddy explore the brand new Elizabeth Line – and have access to 2 of its stations weeks before the line opens. Siddy also explores the disused parts of Angel.

Visit one of London Underground’s most secret places: North End under Hampstead Heath. Abandoned before completion, the station became a Cold War bunker.

Explore the hidden parts of Euston, including unique features not found elsewhere and the bits set for demolition for HS2. Siddy also visits York Road station.

Tim Dunn and Siddy Holloway explore the abandoned branch line between Holborn and Aldwych. And at Holloway Road they find out about the Tube's only spiral escalator.

Tim and Siddy visit the cathedral-like Greenwich Power Station, which stands ready to power the tube at short notice. Siddy visits hidden parts of Notting Hill Gate.

Tim and Siddy explore Kings Cross St Pancras, including a secret siding and the disused Thameslink station. Siddy also discovers long lost Marlborough Road station.

New. Tube fans would be right in thinking there are 272 Underground stations, but Siddy Holloway has such unique access, she is taking Tim Dunn to the 273rd - West Ashfield.

Tim and Siddy go under the platforms of Paddington station. It has five different tube lines running through it, with its oldest and newest lines opening 150 years apart. Tim explores a tunnel still in use under the mainline station, but with intriguing clues as to its original purpose. Siddy discovers some former police cells underneath the platforms, and unearths what remains of the luggage carousels from when passengers on the Heathrow Express were allowed to check-in their luggage in the main station. At Tottenham Court Road, Siddy reveals the huge changes to the station to accommodate the Elizabeth line, and tells the story of how the station’s iconic mosaic artwork was preserved during the works. She also takes us behind a locked door to uncover a floodgate installed as part of Britain’s Cold War defences. Back at our Museum depot in Acton, Tim meets a young tube driver who’s built up a large following on social media for her posts showing behind the scenes of her job.

Tim Dunn and Siddy Holloway discover the hidden corners of Shepherd's Bush.

Tim and Siddy are heading to a station you won’t find on modern-day tube maps – Dover Street, now known as Green Park. During the Second World War the abandoned passageways and lift shafts of the original station had an incredible second life as the base for the London Passenger Transport Board whose work kept London’s transport moving against all odds. Next, Siddy delves into the abandoned corridors and platforms of Down Street, closed to the public in 1932, and the scene of some of the most pivotal decisions of World War II.

Tim Dunn and Siddy Holloway are exploring a station in the beating heart of London's theatreland - Leicester Square.

Tim and Siddy explore the disused parts of London Bridge. Siddy visits Ongar in Essex, and nearby Blake Hall which, at the end, served less than 20 passengers a day.

Tim and Siddy explore the forgotten underground passages and tunnels underneath one of Britain’s busiest railway stations, Waterloo. Tim gets a tour of a hidden world underneath the main concourse, which includes a former typing pool, a rifle range and a full-size snooker table gathering dust. As a member of our Hidden London team, Siddy has the key to unlock a door to a secret room at the end of a Bakerloo line platform. She discovers a floodgate which would have sealed the tunnel entrance during German bombing raids over London during the Second World War. Siddy visits Marble Arch on the Central line, and meets the artist who created an iconic series of enamel artwork on the platforms in the 1980s. Each depicts the Marble Arch in a different design, and they’re still in pristine condition after 40 years. Siddy hears how the designs came about, and how the artist had to learn the intricate craft of working with enamel to realise her vision.

Tim and Siddy embark on a night-time track walk to the abandoned station of British Museum. The pair discover 1930s hand-painted adverts and white tiling. During the second world war it served as a shelter and spine-tingling clues to the children who stayed there during The Blitz can still be seen. Siddy also visits the houses of Leinster Gardens.

Tim Dunn and Siddy Holloway head to the sprawling Heathrow Airport underground stations - the first ever underground rail link between an airport and a city