The UK is not subordinate to the US. The US does not direct UK policy.
it relies on military protection from US
No, it doesn't. The UK has its own military, and it's own military-industrial complex. The UK is not at war. It's in a co-operative military alliance, so if someone like Russia came to invade, the US would assist.
can't have a sovereign and independent policy
The US does not give a shit about the UK's policy. The UK can do what it wants.
You're literally just making stuff up, this is like flat-earth level content.