Apparently a few have been convicted, but certainly not a high number.
It would be interesting to see how many UK cop killings were in NI, rather than mainland, as part of the over all stats. I consider the police in NI, certainly back in the day, more aligned with the army that mainland policing.
That all said, I would rate our (I’m from the UK) police way, way higher in terms on being a police officer, being approachable, being useful/helpful, being competent and extremely unlikely to kill me.
I am not black or otherwise brown skinned, so take that into account.
Given that, I actually feel a lot safer with my home country police than any other country I have travelled to in the last 30 years, with the exception of the Nordics.
I stopped travelling to the US for work (W*M) a couple of years back due to the fact I could no longer go there, despite loving the people on the ground and the countryside. I do not currently consider the US to be a safe place to visit, due to the police, border controls and, of course, the baby in chief.