Caporegime
The problem is a 15-20% payrise to doctors wouldn't suddenly magically make the NHS run better. It might lift the morale of doctors briefly, but with the same hours and demands being placed on the NHS we'd be back to square 1 in a few months.
Ideally Doctors hours need to be cut and more of them recruited. That way they're not overworked/exhausted, and with the hours they'd be expected to work you'd assume higher productivity levels.
What is needed is a combination of valuing existing staff, that would be a combination of pay/simplifying barriers to extra work/fixing the pension scheme/funding professional development alongside investing in the long term staffing situation.
Currently we don't train enough nurses/doctors, we don't retain the ones we've got and we're on course to everything just falling over in the near future (it feels entirely intentional to most of us at this point).
The likelihood is once the NHS collapses everyone that was working within it will see a substantial increase in pay and better working conditions.