Michael Portillo unlocks the doors to four extraordinary abandoned locations. Since it opened 400 years ago, Shepton Mallet prison has seen thousands of prisoners, numerous executions and countless escape attempts. It has been home to gangsters, and during the Second World War a safe house for Britain's most precious historic documents such as the Magna Carta.

Built in the East End of London 250 years ago and closed in 2013, the Royal London Hospital pioneered medical breakthroughs and healthcare for generations of people.

In 1943, the village of Imber in Wiltshire's Salisbury Plain began to be used as a Second World War training ground. At risk from friendly fire, each household was ordered by the War Office to abandon its home for the duration of the conflict. Despite promises that the residents could return after the war, the village remains in the hands of the military, and has been since used for training against the IRA and the Taliban. Michael meets former residents and relatives to hear this story of upheaval, and talks to historians to reveal the history behind the desolation of this ancient village.

Michael Portillo unlocks the doors to four extraordinary abandoned locations. For almost a century, Orford Ness was owned by the MOD, a lens into a bygone era of secrets, spies and superpowers. When it closed in 1993, its buildings were still shrouded in secrecy.