QoH I am not a practicing PA in the UK (I'm not even practicing in the USA, still a student) but I do have long term interest in moving to the UK. I have been keeping an eye on how things are developing with PAs over there.
I'm not sure how you are connected to the UK so I will assume you have a work visa already figured out. The NHS is by far and away the largest employer in healthcare. There are private hospitals but I'm not sure if they use PAs. The NHS has been utilizing PAs increasingly and the number of PA schools has grown to about half a dozen or so.
The UK PA association is part of the Royal College of Physicians, is the Faculty of Physician Associates.
There is a bunch of information on their website http://www.fparcp.co.uk/faqs/
The highlights are that
1) American trained PAs can work in the UK.
2) PAs have a more limited scope. They are unable prescribe and cannot order ionizing x-rays or CTs
3) Salaries are much lower, working for the NHS means that salaries are predetermined and arranged in bands and grades. PAs start at Band 7 (~31K GBP) with 5 years of experience you can move up to band 8a which tops out at 48K GBP. Far less than over here with a far higher cost of living....especially in London.
Another point to highlight from there webpage is: "Employers are usually looking for physician associates with a number of years of experience. Now that there are UK universities educating physician associates, there will be many home-grown physician associates looking for jobs so it will be necessary to recruit locally"
For me it is still a little ways off before I seriously consider moving back. My hope is by then the NHS will be utilizing PAs with an increased scope and corresponding increased salary. We shall see, but if anywhere could use the improvements in efficiency and cost lowering that PAs bring to the table it is the NHS.
EDIT: There are actually 24 active programs in the UK with 4 more starting in 2017 and more in development! Looks like PA programs are growing as fast over there as they are over here!