Secrets of the London Underground Episode Rating Graph

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.

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 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 disused parts of Piccadilly Circus, the grandest station on the London Underground. And they also visit the long-abandoned Highgate surface 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 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 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 are exploring a station in the beating heart of London's theatreland - Leicester Square.

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

Tim Dunn and Siddy Holloway explore the labyrinthine Camden Town station, and the forgotten wartime shelter built beneath. Plus, Siddy visits a station which hides a lost river.

Tim Dunn and Siddy Holloway snoop around TFL's gargantuan maintenance facility - Acton Works