.This is a rough and ready overview of the British Army in the late '70's. Sources disagree about manpower figures and the constant minor organisation changes are a headache to keep up with, especially as paper and practice were often quite divergent.
In 1972 all troops within the UK came under the Commander in Chief United Kingdom Land Forces (C-in-C UKLF), with lieutenat-general as deputy. C-in-C headquarters being based at Erskine Barracks, Wiltshire (Salisbury Plain). His command extended to British forces in Belize and at the Suffield exercise area in Canada but NOT Northern Ireland.
Within UKLF there were nine semi-autonomous military districts. South-East and Scotland Districts are commanded by a lieutenat-general, the rest major-generals. As of June 1976 these were:
South-East: 17,500 Regulars, 8,000 Territorial Army
South-West: 19,500 Regulars, 3,000 Territorial Army
London: 12,000 Regulars, 7,000 Territorial Army
North-East: 9,000 Regulars, 10,000 Territorial Army
Eastern: 8,500 Regulars, 7,000 Territorial Army
West Midlands: 5,000 Regulars, 4,500 Territorial Army
Scotland: 4,000 Regulars, 8,000 Territorial Army
North-West: 2,000 Regulars, 7,000 Territorial Army
Wales: 1,500 Regulars, 3,500 Territorial Army
Following the 1974 Defence Review which imposed swingeing economies on the Armed Services, regular divisions and brigades in the UK disappeared and were replaced by 1977 with 6th Field Force (formed from HQ 16th Parachute Brigade), 7th Field Force (formed from 19th Infantry Brigade), and 8th Field Force (formed from HQ 5th Infantry Brigade). The Field Forces were superimposed onto existing district commands and as a rough rule of thumb contained 3 regular and two territorial infantry battalions plus assets.
6th Field Force became the strategic reserve for SACEUR. Taking over from 3rd Division as UK Mobile Force it boasted a parachute element from the re-organised 16th Parachute Brigade, with HQ at Aldershot, South-East District. The air element assigned to 6th Field Force was 2 squadrons of jaguars and 22 Puma Helicopters.
7th Field Force, mapped to Eastern District at Colchester was destined to be the BAOR reserve, whilst 8th Field Force, mapped to South-West Dsitrict at Bulford was the C-in-C UKLF reserve for home defence.
The United Kingdom's contribution to Allied Command Europe Mobile Force (Land) or ACE Mobile Force(L) in 1979 was one squadron of Harriers, four Puma776W helicopters, an infantry battalion group, a logistic support battalion and other support troops 1,500 men stationed at Dover. ACE Mobile Force (L) was destined to be part of an international NATO brigade sized unit to be deployed in Norway or Turkey as required.
Outwith the tactical units there are of course many tens of thousand of soldiers in all the service corps, (RAMC, RAOC, REME, Royal Signals, Military Police etc), training and administrative functions of the army in the UK. Add to this Royal Navy and Royal Air Force personnel. The vast majority of whom are capable of standing to and taking up arms as required - though readiness and resolve may be questionable (within the context of gaming an internal crisis).
In addition to the 89,000 Regulars and 58,000 Territorial Army in the UK, 61,000 British troops were based in Europe, of which 55,000 were in the British Army of the Rhine (BAOR). Further troops, including the Brigade of Gurkhas were stationed in protectorates and the few remaining colonies - such as Hong Kong. One battalion of Gurkhas was based in the UK.
Northern Ireland was garrisoned by 12,000-15,000 British servicemen divided into 3 Brigade commands. There were 5 'garrison' battalions which were supplemented as the situation required by other formations on short, roulement or emergency tours. A 6th 'garrison' battalion was added in 1978 and a 7th in 1979/80. The Ulster Defence Regiment, created for duty within the province in 1970, had 8,000 full and part-time soldiers by 1978.
Finally but not least, 3 Commando Brigade consisted of 40,41, 42 and 45 Royal Marine Commandos. Two Commandos were based at Plymouth and Deal(?), 45 Commando was based at Arbroath. The Royal Marines maintained a worldwide force projection role so deployment in the UK varied continuously.
Rounding up, 29 regular infantry battalions were stationed in the UK. It was envisaged that 2 battalions at least would be available to each District command in a war. Of the Territorials 25 per cent of the total BAOR wartime strength would have been Territorial Army and of the 88 infantry battalions in BAOR during a war 38 (43%) would have been Territorials.