pro-British assembly members could counter the ATUC's influence. However, the day after State of Aden joined the federation the Muhammad al-Badr of the Yemenese monarchy was overthrown and civil war ensued between forces backed by Gamal Abdel Nasser such as the National Liberation Front (NLF) and monarchist forces backed by the Saudi Arabia and the United Kingdom. Internal disturbances continued and intensified, leading on 10 December 1963 to the Aden Emergency, when a state of emergency was declared in the largely dysfunctional Aden State. Other events of the conflict that kept spreading throughout the region include the Battle of the Crater which brought Lt-Col Colin Campbell Mitchell (AKA. "Mad Mitch") to prominence. On June 20, 1967 there was a mutiny in the South Arabian Federation Army, which also spread to the police. Order was restored by the British, mainly owing to the efforts of the 1st Battalion Argyll and Sutherland Highlanders, under the command of Lt-Col Mitchell. Nevertheless, deadly guerrilla attacks against British forces, particularly by the Egyptian-supported National Liberation Front (NLF), soon resumed in all their intensity. British presence finally ended with the final departure of British troops. The withdrawal was undertaken earlier than had been planned by British Prime Minister Harold Wilson and left the future state without an agreement on the succeeding governance. Finally the enemies of the State of Aden and the Federation, the NLF, managed to seize power. On 30 November 1967 Aden State, together with the federation, became the People's Republic of South Yemen. In line with other formerly British Arab territories in the Middle East, the independent state did not join the British Commonwealth. The South Arabian dinar, however, continued at the one to one parity with sterling until 1972. See also Aden Protectorate British Forces Aden Aden Emergency References Further reading Edwards, Aaron. "A triumph of realism? Britain, Aden and the end of empire, 1964–67." Middle Eastern Studies 53.1 (2017): 6-18. Gavin, R.J. Aden Under British Rule: 1839–1967 (C. Hurst & Co. 1975). Hinchcliffe, Peter, et al. Without Glory in Arabia: The British Retreat from Aden (2006). Mawby, Spencer. "Orientalism and the failure of British policy in the Middle East: The case of Aden." History 95.319 (2010): 332-353. online Mawby, Spencer. British Policy in Aden & the Protectorates, 1955-67: Last Outpost of a Middle East Empire (2005). Walker, Jonathan. Aden Insurgency: The Savage War in South Arabia 1962–67 (Spellmount Staplehurst, 2003) External