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.

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 visit Quainton Road in rural Buckinghamshire, 50 miles from central London – and once on the underground. Siddy also explores Kingsway tramway tunnel.

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.

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.

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 walk the Piccadilly line at night to explore the hidden World War 2 remains of Brompton Road. Siddy reveals the unexpected wartime use for St Pauls.

Tim and Siddy visit King William Street, the earliest disused station on the deep tube. Siddy also sees new life breathed into Knightsbridge’s long-abandoned lifts.

Tim Dunn and Siddy Holloway go off and discover the hidden world of the Waterloo and City. This is the only line that is entirely underground.

Tim Dunn and Siddy Holloway make their way over and explore the disused Jubilee line areas of Charing Cross station, which is now more famous as a film location.