Having done some digging, the British Armed forces in 1972 were 371,400 strong. Of that, 175,850 were army personnel, not including reserves of 55,000 in the Regular Reserve, and a further 80,000 people in the Territorial and Army Volunteer Reserve.
As mentioned above, 29 battalions with an average strength of 690 men were already deployed to Norther Ireland (20,010 in total). So that leaves 155,840 men available to the British government, not including other branches. The question is how many can be deployed?
A significant proportion of the Army's strength was deployed overseas, the biggest chunk of which was the British Army of the Rhine, numbering 51000. A further 30,320 were based in the Middle East. More were scattered around the globe, but those were the two major concentrations. So assuming that ~15000 were otherwise engaged around the world (a number that I have pulled from nowhere but simply to guess at troop deployments)that leaves about 60,000 troops for the UK government to play with. I am as we speak digging through the national archives trying to find the actual exact number of troops in Great Britain that could be sent to Ulster but it's a bit finickity as many of the archives haven't been digitised. I will update this if I find anything better or if someone who actually knows about troop numbers in the 70s intervenes in the thread( which seems likely).
So assuming that the UK gov doesn't send any of its troops away from the Rhine or the middle East (which seems unlikely given this would be to tackle ETHNIC CLEANSING on UK soil!) it still has 60k men to crack this nut. Which added to previous numbers would be 80000 heavily trained, heavily armed, pissed off professional soldiers to hunt down (tops) 3000 nutjobs. Even if the entire former Ulster Special Constabulary do throw their lot in with the the secessionists(which I would doubt as they don't WANT to fight the Army or the British Government), I wouldn't fancy their chances.
I would feel sorry for the UDI if they weren't the dregs of the earth. Same for any IRA nutters who try their luck against an army with the RoE adjusted to fight a war.
Sources:
https://api.parliament.uk/historic-hansard/commons/1970/mar/12/army-estimates-1970-71-vote-a
In 2020 there were over 145 thousand personnel serving in the British Armed Forces, the second-fewest of any year since 1900, with just 144 thousand serving in 2019.
www.statista.com
Nice work.
The Ulster Special Constabulary (B-Specials) I think would go with the UDI. There is also the UDR too who would side with UDI too.
en.wikipedia.org
Some units of the British army that recruited in the republic of Ireland at the time might not be sent for political reasons.
if the UDI forces are smart they will not fight a conventional war against the British army.
Start off with ordering a boycott of the British army banned civilians from supplying any aid or comfort to the British army.
Strikes at the ports and airports to stop the British army from sending more men and supplies.
If that works the British army might have to ask the Republic of Ireland to land in an Irish port to transit to and supply the Army in Northern Ireland.
Or they could do a D-day and land amphibious troops from beach land craft.
The British army will not be able to trust the phone system as this is easy to tap in to on the manual phone exchanges of the time.
They will need to team of enforcers to make examples of those who supply the British army in Northern Ireland or provide intel to them.
UDI will have their own spies in the British army.
What happens next will depend on what tactics the unionist adopt. I think they would be foolish to defend fixed ground.
British army shows up numbers and they leave and return when the British have moved on.
Better to fight only on terms favourable to the UDI forces. Much of the British army will be defending Nationalist enclaves and supplying them with food and medicine etc.
The more areas that are attacked the more troops that need to be assigned to fixed positions to defend them.
I could see them blowing bridges and transport links to block the movement of British army troops. Roadside bombs and IED would make the army need to be very careful.
Sniper attacks too.
The British army could be forced to use helicopters to move around.
The UDI forces should know their home ground better than the British army.
I am not sure what weapons the UDI forces have.
They could make their own.
They could steal British army ones and there is also smuggling of weapons.
UDI should be a lot larger and better armed than the IRA in the war of independence.
IRA had about 3,000 men on paper underarms and very short of arms and ammo often using reloaded ammo.
up to 100,000 volunteers on paper doing logistics cutting phones lines digging up roads etc
I wonder will Gusty Spence and loyalist prisons be released or allowed to escape from long kesh.
en.wikipedia.org