That more the result of stupidity and Napoleon syndrome than some magic hold the US has over the UK. The UK, in particular our government, still wants to believe we're a geopolitically important country capable of projecting power and influencing the world. While there's some small element of truth in that belief, our actual relevance on the world stage is far small than our government wishes it was, and is only getting smaller thanks to wonderful incompetence of past 10 years of government.

  >Either way, it’s not the fault of the US if the UK acts as a vassal state...

It's only in the US and amongst a self-deluding swathe of British society that this "relationship" is seen as one of equals. The reality is that we're sucking up to the playground bully because we've seen what he does to the kids who won't hand over their dinner money. And we're trying to kid ourselves we're best buddies.

To be fair, most voters in the UK didn't vote for the current government.

https://en.wikipedia.org/wiki/2019_United_Kingdom_general_el...

What is a good example?

  >> UK just immediately follows whatever the US does, even if it is economically suicidal.

  >>What is a good example?

But there are plenty of others, including needlessly antagonising China and sabotaging our previously beneficial economic relations, because the US is spoiling for a fight with China. Ergo UK must do likewise.