Episodes airing soon

  • Clapham

    Tim Dunn and Siddy Holloway explore Clapham South deep level shelter where thousands of Londoners slept in the war.

  • Clapham

    Tim Dunn and Siddy Holloway explore Clapham South deep level shelter where thousands of Londoners slept in the war.

  • Charing Cross

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

  • Waterloo and City

    Tim Dunn and Siddy Holloway discover the hidden world of the Waterloo and City, the only line entirely underground.

  • King William Street, Knightsbridge

    Tim Dunn and Siddy Holloway explore King William Street, the original terminus of the first electric Tube in the world.

  • Brompton Road

    Tim Dunn and Siddy Holloway walk the Piccadilly line at night to explore the hidden World War 2 remains of Brompton Road.

  • Baker Street

    New. Tim Dunn and Siddy Holloway explore the tube ststaion with the most platforms, Baker Street.

  • Baker Street

    New. Tim Dunn and Siddy Holloway explore the tube ststaion with the most platforms, Baker Street.

  • St Marys

    Tim Dunn and Siddy Holloway have a night-time track walk exploring long forgotten stations on the District line in Whitechapel.

  • London Bridge

    Tim Dunn and Siddy Holloway explore the disused parts of London Bridge. Siddy visits Ongar in Essex and nearby Blake Hall.

  • Kings Cross

    Tim Dunn and Siddy Holloway explore Kings Cross St Pancras, including a secret siding and the disused Thameslink station.

  • Elizabeth Line

    Tim Dunn and Siddy Holloway explore the brand new Elizabeth Line and have access to two of its stations weeks before the line opens.

  • Quainton Road and Kingsway

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

  • Greenwich Power Station

    Tim Dunn and Siddy Holloway visit the cathedral-like Greenwich Power Station, which stands ready to power the tube at short notice.

  • Holborn

    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.

Episode guide

Secrets of the London Underground

Series 1

Secrets of the London Underground

  • North End

    Tim Dunn and Siddy Holloway visit North End under Hampstead Heath. Abandoned before completion, the station became a Cold War bunker.

    Not scheduled
    Not scheduled

  • Holborn

    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.

  • Piccadilly

    Tim Dunn and Siddy Holloway explore the disused parts of Piccadilly Circus, and visit the long-abandoned Highgate surface station.

    Not scheduled
    Not scheduled

  • St Marys

    Tim Dunn and Siddy Holloway have a night-time track walk exploring long forgotten stations on the District line in Whitechapel.

  • Euston

    Tim Dunn and Siddy Holloway explore the hidden parts of Euston, including unique features not found elsewhere and the bits set for demolition for HS2.

    Not scheduled
    Not scheduled

  • Clapham

    Tim Dunn and Siddy Holloway explore Clapham South deep level shelter where thousands of Londoners slept in the war.

Secrets of the London Underground

Series 2

Secrets of the London Underground

  • Quainton Road and Kingsway

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

  • Elizabeth Line

    Tim Dunn and Siddy Holloway explore the brand new Elizabeth Line and have access to two of its stations weeks before the line opens.

  • Charing Cross

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

  • Baker Street

    New. Tim Dunn and Siddy Holloway explore the tube ststaion with the most platforms, Baker Street.

  • Kings Cross

    Tim Dunn and Siddy Holloway explore Kings Cross St Pancras, including a secret siding and the disused Thameslink station.

  • London Bridge

    Tim Dunn and Siddy Holloway explore the disused parts of London Bridge. Siddy visits Ongar in Essex and nearby Blake Hall.

  • Brompton Road

    Tim Dunn and Siddy Holloway walk the Piccadilly line at night to explore the hidden World War 2 remains of Brompton Road.

  • Waterloo and City

    Tim Dunn and Siddy Holloway discover the hidden world of the Waterloo and City, the only line entirely underground.

  • King William Street, Knightsbridge

    Tim Dunn and Siddy Holloway explore King William Street, the original terminus of the first electric Tube in the world.

  • Greenwich Power Station

    Tim Dunn and Siddy Holloway visit the cathedral-like Greenwich Power Station, which stands ready to power the tube at short notice.