Not a lot. The British weapons are reliant on US maintenance. Won’t be credible for long if the US doesn’t support them.
Isn’t this a bit like saying that because I drive a German car that’s maintained by the dealership, it’s not my car?
I’m sure it wouldn’t be tricky for the UK to move the Trident weapons program closer to home, or to align with allies in Europe (lol).
By the time Russia is knocking at the door of the UK, its already game over.
That said, I would not want to be Polish right now.
Russia can barely project power across its own border, what chance has it got of projecting all the way to the British isles? We have more aircraft carriers than they do and ours actually work.
Russia is a spent force. All they have is their rusty old nukes as a threat and I highly doubt they’ll ever actually use them.