Research published today confirms that the problem is particularly acute in London where more than one advert in two fails to result in an appointment.
The survey of senior staff appointments by Education Data Surveys was based on headships advertised in The TES, Times, Guardian and Independent.
It reveals that by the end of 2000, 12 per cent of secondaries and 11 per cent of primaries had advertised for a new head.
Church schools still experience most problems finding suitable heads, with more than half of the top postsin Catholic schools being readvertised.
As schools struggled to attract staff, wages rose. London primary heads' salaries now regularly top pound;50,000. The number of primary headships advertised was 40 per cent higher than the total for 1999.
Few secondaries offered less than pound;60,000 per annum.
EDS managing director John Howson predicted that some heads' salaries could hit six figures in the next couple of years. In March 1999, an average secondary head earned pound;45,000 and a primary head pound;32,500.
Michael Murphy of Crown Woods school, Eltham, south London, is the highest paid head in the state sector, earning pound;92,000.