I'm seeing a lot of international messages getting this wrong, so this is how you refer to the Prime Minister of the UK.
First, we normally refer to the PM just by name, like anyone else. So, "Keir Starmer" or "Mr Starmer".
"Prime Minister" is not used as a title like "President" is. He's not "Prime Minister Starmer". He's just "the Prime Minister" or "the Prime Minister, Keir Starmer".
Unusually, this new PM is also a knight. Of course, this has its own rules.
If you want to use this title, it's not quite as simple as replacing "Mr" with "Sir'. The first name is more important than the surname here. He's not "Sir Starmer". He's "Sir Keir Starmer" or "Sir Keir".
I figured this was going to be somebody wanting to talk about his politics or something like that but no it's just a pedantic Englishman pissed that people are using the wrong title
That always ends up happening. Whenever a government has being in power for too long they start to break into 90 different factions and spend their entire time fighting each other, and not getting anything else done.
Also a certain group of the Conservatives have started to play by the Republican Party playbook, while the rest of them are politely asking if maybe they could not be fascists? Of course appeasement never works so apparently the next best option is to have giant arguments about it and replace the PM every 10 minutes.
Fortunately Labour are another party, and regardless of what you think about them as a party, they are at least different and are less fractional currently, so perhaps now we can get something done.