The Scout formed the backbone of the Army Air Corps throughout the 1960s and well into the 1970s; the first Scout flew on 29 August 1960 and an initial order for 66 aircraft followed a month after its first flight. Engine problems delayed the introduction of the Scout until 1963, and as an interim measure the Army Air Corps received a small number of Allouette II helicopters. Although the aircraft's entry into service was delayed, the Scout still had a number of teething troubles when it was introduced. One of the earliest losses was XR596, which crashed into the jungle near Kluang airfield in Southern Malaya, 16 July 1964, following a fuel pump failure. The two crew died in the incident. Engine failures were responsible for the loss of at least eleven military and civilian registered aircraft. The engine life of the Nimbus during the early part of its service was notoriously low, with four to six flying hours being the norm. A competition was allegedly held, with a prize to the first unit that could achieve an engine life of twenty-five flying hours. Operational experience and development work steadily improved the reliability of the Nimbus and by 1964 engine life had improved to two/three engine changes per 1,000 flying hours.
The Scout AH Mk 1 was operated by the Army Air Corps on general light work, including observation and liaison. Like the Wasp, the Scout could be fitted out with different role equipment including flotation gear and a Lucas, air-driven hoist which had a lift capacity of 600 lb (270 kg). In the light attack role it was capable of carrying one pintle machine gun in the rear cabin (it is possible to carry two pintle mounted GPMGs in the cabin, although this would, unsurprisingly, be somewhat cramped) or two forward-firing 7.62mm L7 General Purpose Machine Guns (GPMGs) fixed to the undercarriage skid. These GPMG combinations were sometimes used in unison to great effect.
The forward firing GPMGs were electrically operated, being fired by the pilot and aimed using a rudimentary system of drawing a small cross on the windscreen with a chinagraph pencil. In sandy conditions these weapons could jam, which necessitated one of the free crew to lean out of the cockpit door and 'boot' the offending weapon in hope of clearing it. This procedure was not strictly in accordance with the flight reference cards. The L7A1 pintle mounted weapon was operated by a door gunner.
The way British Military Aviation has been established has meant that the Royal Marines have never actually “owned” their own aircraft. The larger Whirlwind, Wessex and Sea King helicopters have been “Royal Navy” Helicopters and, like today’s Lynx AH Mk 7, the Scout AH Mk 1s operated by 3 Commando Brigade Air Squadron (3 CBAS) were British Army helicopters on loan. 3 CBAS flew the Scout from 1979 through to 1982, when the Scout was replaced by the Westland Lynx, and the squadron was eventually renumbered as 847 Naval Air Squadron.
The Scout saw operational service in Borneo, Aden, Oman, Rhodesia, Northern Ireland and then in the South Atlantic.
The Territorial Army (AAC) formed 666 Squadron with a number of Scouts in the late 1980s.