Seven people died and 76 were injured when a train derailed and crashed into the station, on May 10, 2002.

Potters Bar: The Truth, due to be screened at 9pm on BBC 1, is billed as a fascinating and thought-provoking film by Jane Sayers.

It follows the British Transport Police and the Health and Safety Executive during the huge inquiry into the cause of the accident.

The programme shows them examining claims of sabotage and reveals their findings have implications for the whole rail industry.