If that's sub-threshold for you, I'd also add the 1919 to 1921 Irish War of Independence as, likewise with the Troubles, it was part of the UK at the time.
Personally, I would also argue that almost all of the independence movements in the former colonies count as examples of the governments of the UK being "not stable" even though those colonies were outside the nation itself, and that would even extend to cases like Malta where independence happened peacefully after a proposal to give them a seat in Westminster, and not just cases like Cyprus where they used guns to kick us out and yet somehow the British Sovereign Base Areas are still there.
> or invited in a new royal family?
1689, which you may feel is a while ago now, but the USA Revolutionary War was 1775, and proportionally speaking that invitation was only 34% longer ago than the formation of the USA, so I wouldn't call it an "extremely" long history relative to that… even if you don't want to count the Revolutionary War itself as an example of instability in the British government, which I would as the British was the other party in that conflict.
I don't really consider the Troubles to be a Civil War. Even Wikipedia is making a distinction and calling it an "irregular war" or "low-level war".
So the last time a civil war happened was 100 years ago. That seems decently stable. The war itself was quite minor as well. Wikipedia says 2300 people died with 900 of them being civilians. A two year war with less than 1,500 soldiers dying isn't exactly that unstable. It is more of a dust up (I understand it is causing all sorts of conflicts even to this day).
When it comes to Cyprus and the like I don't really call it unstable. Did Cyrpus leaving cause any issues to the UK? Would the average person have even known where Cyprus is located let alone what was happening? Calling it a civil conflict or whatever may be technically correct but feels different. English isn't even an official language of Cyprus (I assume it was back when the UK was in charge?). People in the UK probably didn't have family in Cyprus. People a thousand miles away leaving isn't that big of a deal.
As for the US Revolutionary War, there were 10s of thousands dead from the war. This was more than just a dust up. How is a few hundred years not a long history? I've seen some estimates that say the average existence of a country is 150 years.
What I'm arguing against is the claim "the UK has an extremely long history of relative stability compared to basically anywhere else on the planet".
For that, "decently stable" isn't good enough, it has to be remarkable stability.
> Did Cyrpus leaving cause any issues to the UK?
Given this happened during the collapse of the British Empire, it's difficult to say exactly what fraction of the many issues facing the UK in that era were due to any specific one of the many things that changed in rapid succession. For example, the Cyrpus conflict began before the Suez Crisis, but continued for several years after.
However, the continued presence of the air bases suggests that it was considered important by the UK government.
> English isn't even an official language of Cyprus (I assume it was back when the UK was in charge?).
English was the sole official language during British colonial rule and the lingua franca until 1960, and continued to be used in courts until 1989, and in legislation until 1996.
1998: https://en.wikipedia.org/wiki/The_Troubles
If that's sub-threshold for you, I'd also add the 1919 to 1921 Irish War of Independence as, likewise with the Troubles, it was part of the UK at the time.
Personally, I would also argue that almost all of the independence movements in the former colonies count as examples of the governments of the UK being "not stable" even though those colonies were outside the nation itself, and that would even extend to cases like Malta where independence happened peacefully after a proposal to give them a seat in Westminster, and not just cases like Cyprus where they used guns to kick us out and yet somehow the British Sovereign Base Areas are still there.
> or invited in a new royal family?
1689, which you may feel is a while ago now, but the USA Revolutionary War was 1775, and proportionally speaking that invitation was only 34% longer ago than the formation of the USA, so I wouldn't call it an "extremely" long history relative to that… even if you don't want to count the Revolutionary War itself as an example of instability in the British government, which I would as the British was the other party in that conflict.