Aden, commanding the entrance to the Red Sea, was an important British air and naval base on the route to India and had been occupied since 1839. In January 1963, this British colony was merged with the sheikhdoms of the Aden Protectorates to form the Federation of South Arabia. This was done against the wishes of much of Aden city's population. In 1964 Britain announced that independence was to be granted to the Federation by 1968, but that British forces would remain in Aden.
Arab nationalists resented this and, egged on by President Nasser of Egypt, formed the National Liberation Front (NLF) in Yemen, which itself had designs on Aden and its hinterland. An insurgency against British rule known as the Aden Emergency began with a grenade attack by the NLF against the British High Commissioner on 10 December 1963, killing one person and injuring 50.
Trouble then developed in the mountainous Radfan region, where dissident local tribesmen raided the road connecting Aden with the garrison town of Dhala, on the Yemen border. In January 1964, three Federation Regular Army (FRA) battalions, with British air support, restored order, but when they withdrew, trouble flared up again, with the rebels receiving NLF support.
On 29 April a second expedition was mounted. This time British ground troops were involved in the operation. Together with two FRA battalions they advanced rapidly through difficult terrain, capturing the ridges and hills that dominated the tribal areas. By 26 May 1964 they had taken the main rebel stronghold in the Wadi Dhubsan and suppressed the tribal revolt.
From November 1964, the NLF switched its efforts to Aden itself, where it began an urban terrorist campaign. British troops and their families, members of the local security forces and supporters of the government were all attacked. Although Special Air Service (SAS) operatives were covertly deployed against the terrorists, the NLF’s campaign of intimidation made it difficult for the security forces to gather intelligence, as the local population was unwilling to co-operate with them.
In 1966 the British Government announced that all British forces would be withdrawn on independence. Few locals in Aden believed that the existing government would survive without British support and were therefore wary of being seen to support it. As the NLF escalated their attacks, a second nationalist group, the Front for the Liberation of Occupied South Yemen (FLOSY), also began terrorist activities against the security forces.
In January 1967, there were riots by the supporters of both groups in the old Arab quarter of Aden. These continued until mid-February, despite the intervention of British troops. Morale amongst the local security forces was now at an all time low and on 20 June 1967 a mutiny in the Federation Army spread to the Police. Eight soldiers of the Royal Corps of Transport were killed when mutineers fired on their lorry.
Order was quickly restored, but rumours that the British were shooting mutineers led to a number of ambushes in the Crater area of Aden and the deaths of a dozen more soldiers, including men from 1st Battalion, The Argyll and Sutherland Highlanders. Two weeks later, Lieutenant-Colonel Colin Mitchell led the Argylls back into Crater, which was reoccupied in a blaze of publicity.
As the date for the British withdrawal in November 1967 approached, the NLF and FLOSY began fighting each other for control of Aden, with the NLF gaining the upper hand. In the last week of November the remaining 3,500 men of the British garrison were evacuated. The Royal Marines, who had been among the first British troops to occupy Aden in 1839, were the last to leave - with the exception of a Royal Engineer detachment.
Following a short civil war, Aden and its hinterland became part of the Marxist People’s Democratic Republic of Yemen. In 1990 this merged with North Yemen to form the Republic of Yemen. Aden was the British Army’s last colonial counter-insurgency campaign and one of its least successful. The British withdrawal from Aden completed its retreat from Empire, which had started 20 years earlier with the independence of India and Pakistan.