President Sallal of the Yemen, second from left, with Yemeni tribesman at the Jund conference near Taiz. They are discussing the expulsion from the country of Iman Muhammad al-Badr and his family because of the harm they have caused to the Yemeni people. (Photo by Keystone/Getty Images). 1965

An Aden civilian crouching in terror as British soldiers threaten him during Arabian demonstrations in Crater. (Photo by Express Newspapers/Getty Images). 1967

A Northumberland Fusilier imposes law and order on Arab demonstrators during a disturbance in the Crater district of Aden. (Photo by Terry Fincher/Getty Images). 1967

British soldiers helping their wounded colleague, after he had been injured by a hand grenade in Aden during nationalist terrorist attacks aiming to expel British forces from South Arabia. (Photo by Express Newspapers/Getty Images). 1967

British soldiers in Aden during nationalist terrorist attacks aiming to expel British forces from South Arabia. (Photo by Express Newspapers/Getty Images). 1967

A soldier of the Northumberland Fusiliers threatening Arab demonstrators in Crater, Aden. (Photo by Express Newspapers/Getty Images). 1967

A soldier of the Northumberland Fusiliers chasing an Arab demonstrator in Crater, Aden. (Photo by Express Newspapers/Getty Images). 1967

The aftermath of violence in Aden, Yemen, during a period of civil conflict and rioting. (Photo by Potter/Express/Getty Images). 4th October 1965

An angry scene in Aden, Yemen, during a period of civil conflict and rioting. (Photo by Potter/Express/Getty Images). 4th October 1965

A British soldier in Aden, Yemen, during a period of civil conflict and rioting. (Photo by Potter/Express/Getty Images). 4th October 1965

A man carrying his belongings on his head in Aden, Yemen during a period of civil conflict and rioting. (Photo by Potter/Express/Getty Images). 5th October 1965

British soldiers in Aden, Yemen during a period of civil conflict and rioting. (Photo by Potter/Express/Getty Images). 5th October 1965

British troops on patrol in Aden. (Photo by Tony Gibson/Express/Getty Images). 16th August 1965

A British serviceman carries out a routine search in Aden. (Photo by Potter/Express/Getty Images). 10th October 1965

The Reverend Raymond Roberts conducting a prayer service for a British Army patrol in Aden. (Photo by Terry Fincher/Express/Getty Images). 24th April 1966

Men from the Royal Navy minesweeper HMS Calton patrol the seas around Aden, searching for dhows running guns to the terrorists, during the country's war for independence. (Photo by Victor Blackman/Express/Getty Images). 23rd February 1966

RAF helicopters bring food and supplies to army outposts in Aden, and rescue the wounded, during the country's war for independence. (Photo by Victor Blackman/Express/Getty Images). 23rd February 1966

Lance Corporal Russell Johnson of the para regiment guards a terrorist escape route outside the lion's cage in Aden zoo. (Photo by Stan Meagher/Express/Getty Images). August 1967

A British soldier stands guard over a wounded Arab demonstrator on the streets of Aden. (Photo by Jim Gray/Keystone/Getty Images). 3rd April 1967

A squadron of British soldiers patrol a street in riot-torn Aden during talks on the future of the South Arabian Federation. (Photo by Jim Gray/Keystone/Getty Images). 3rd April 1967

British troops capture a demonstrator in Aden during rioting over talks on the future of the South Arabian Federation. (Photo by Jim Gray/Keystone/Getty Images). 3rd April 1967

Soldiers of the Northumberland Fusiliers intervene to break up an Arab demonstration in Crater during nationalist terrorist attacks aiming to expel British forces from South Arabia. Aden became the capital of the People's Republic of Southern Yemen in 1967. (Photo by Terry Fincher/Express/Getty Images). 4th April 1967

Soldiers of the Northumberland Fusilier regiment force Arab demonstrators against a wall during nationalist terrorist attacks aiming to expel British forces from South Arabia. Aden became the capital of the People's Republic of Southern Yemen in 1967. (Photo by Terry Fincher/Express/Getty Images). 4th April 1967

A British soldier, wounded in the civil war in Aden, is being put on a stretcher. (Photo by Terry Fincher/Express/Getty Images). 24th June 1967

Soldiers of the British Army (Northumberland Fusiliers) on street patrol during a demonstration by Arabs in the Crater district of Aden during the civil war between republicans and royalists in Yemen. An arab rioter lies on the pavement at the feet of a soldier. (Photo by Terry Fincher/Express/Getty Images). 4th April 1967

Soldiers of the British Army (Northumberland Fusiliers) break up a demonstration by Arabs in the Crater district of Aden during the civil war between republicans and royalists in Yemen. (Photo by Terry Fincher/Express/Getty Images). 4th April 1967

The British army face a group of protestors in Aden, 8th March 1967. (Photo by Terry Fincher/Express/Hulton Archive/Getty Images)