Regarding pay and costs for physicians in the US and UK:
When I left my academic hospitalist position in the US and became a consultant in Scotland, I took a 35-45% pay cut (variable depending on the exchange rate). Had I left a private practice hospitalist job for my consultant post, or left a medical subspecialist (i.e., nephrology, cardiology, etc.) job, my pay cut would have probably been around 60%. Had I been a surgeon and made the transfer to the UK as a consultant, the pay cut could have been as high as 80-90%.
Why the variation? Achievement awards and discretionary ("brownie") points aside, what a UK consultant makes from their NHS contract is solely dependent upon the number of years of experience they have. However, in the US, physician salaries vary widely by what you specialize in and whether you're academic/government versus private practice. Some psychiatrists and pediatricians in the US can struggle to make more than five figures USD. For these physicians, an NHS consultant contract would be a slight pay raise--if they bothered going through the enormous trouble and expense required to transfer your credentials and your self from the US to the UK. Some private neurosurgeons or cardiothoracic surgeons in the US can hit seven figures USD from clinical fees alone. Because of these issues, American consultants in NHS are exceedingly rare (so far, I'm the only one I know of!).
The only exception to the NHS consultant contract is the GP contract. The GP contract is performance based and there is a lot of room for increasing their salary, usually into the low six figure GBP range.
Giantaxe is right. I have an average amount of school debt for a graduate of a US medical school, and my school debt is ~ 50x that of my UK-trained medical colleagues. My malpractice insurance in the US to cover working in critical care at a tertiary referral institution was ~ 30,000 USD/year. My "malpractice" insurance (= medical defence union) in the UK to do essentially the same job is 524 GBP/year.