More than 600 NHS quango chiefs are now on six-figure salaries, with a doubling in the number earning more than the Prime Minister in just three years, new figures show.

Many of the highest earners have made repeated demands on the Government to increase NHS funding as it battles against its worst financial deficit in history.

But figures uncovered by the Telegraph, show that the nine main health quangos are now employing 628 officials on salaries of at least £100,000.