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.

Michael visits the beautiful, forbidding and now abandoned military hospital in the garrison town of Aldershot to uncover the pioneering work of reconstructive surgeons.

In Manchester, Michael ventures inside the London Road Fire Station, which was decommissioned in 1986 after 80 years' service.

Michael Portillo visits a top-secret Cold War stronghold, just a mile from the Cambridge campus where he spent his university years. The bunker, formerly known as RSG-4, was built in 1953 to house 300 local government officials from Cambridgeshire in the event of a nuclear attack. The former politician is also given access to the decommissioned Soviet nuclear submarine U-475 Black Widow - currently moored at Strood on the River Medway - revealing how close the world came to a full-scale nuclear war.

The New Victoria in Bradford was Britain's first cinema.

Michael Portillo explores the history of the British seaside resort. He gets up close and personal with the ghostly skeleton of Brighton's West pier, which has become one of the UK's most well known ruins. He meets Jo Berry, daughter of Conservative MP Sir Anthony Berry who was killed by an IRA bomb at Brighton's Grand Hotel.