MICHAEL Murphy, Britain’s first pound;90,000 superhead may have attracted headlines, but he merits barely a ripple in the private-school sector where the barrier was long since broken.

Nick Tate, former chief executive of the Qualifications and Curriculum Authority, is understood to be earning at least pound;100,000 in his new job as master of Winchester College.

He is one of a growing band whose salaries exceed that figure - even before perks are taken into account. And their wages are increasingly seen as a benchmark for state-sector heads.

The National Association of Head Teachers has now lodged a demand for a “substantial” pay rise saying salaries had fallen up to a third below that for other professionals with similar responsibilities.

Although “superhead” has become an education cliche, only a handful of state heads are paid more than pound;70,000 - and they are mainly in inner London.

Mr Murphy caused a stir when he moved from Hurlingham and Chelsea in west London to Crown Woods in Eltham, south-east London, for pound;90,000 last week.

Salaries in independent schools are jealously guarded secrets, known only to heads, governors and bursar. However, increasing numbers of elite schools, such as Eton, have exceeded the pound;100,000 mark

and their heads salaries generally are rising above the rate of inflation.

One confidential survey revealed that most prestigious schools pay at least pound;90,000. But heads can also expect generous perks - inluding houses and free or heavily-discounted places for their own children - which would take the value of their total package well above this.

However, there is little regional variation among private schools - unlike the state sector which pays pound;2,300 London weighting even before bonuses for taking on challenging schools.

Large private day schools pay around pound;70,000-pound;80,000; girls’ schools slightly less than boys’. But those in small struggling schools can get paid less than state colleagues.

David Hart, general secretary of the NAHT, said: “If independent school heads are worth these salaries for running schools in such privileged circumstances, then heads running highly challenging state schools are worth not a penny less.”

Grant-maintained heads saw their salaries move ahead of colleagues who stayed with local authorities. The Foundation and Voluntary-aided Schools Association says most, but not all, gained up to 2 points on the pay scale. Worth around pound;3,000, this reflects extra duties and larger budgets. Only three state schools - including the London Oratory where the Prime Minister sends his sons - have opted out of the national pay scale altogether.

The NAHT last week released a survey by management consultants Hay McBer comparing heads with other professionals with similar responsibilities. It found that heads of average-sized primaries and secondaries were underpaid by pound;10,000-12,000.

Deputy heads were similarly underpaid, by amounts ranging from almost 12 per cent for those in the smallest primaries to more than 36 per cent in medium-sized secondaries.