The Office for Standards in Education reported today that the proportion of heads providing very good or excellent leadership had more than doubled between 1996 and 2002. Inspectors said the change was “remarkable”.

The proportion of heads whose leadership was very good or better rose from 15 per cent to 40 per cent in primaries and 19 per cent to 47 per cent in secondaries. Poor or unsatisfactory leadership was less common, but continued to affect around one in 20 schools.

A second report, due to be published on Tuesday by the National College of School Leadership (NCSL), will also highlight striking improvements.

However, it will warn that problems recruiting and retaining new heads may hamper future changes.

Geoff Southworth, NCSL director of research, said the high number of heads’ posts being readvertised showed many prospective leaders were reluctant to take on the role.

He said it was worrying that 45 per cent of England’s heads, deputies and assistant heads were over the age of 50.

“Improving retention of senior staff may merit as much attention as keeping newly-qualified teachers,” he said. “Even so, retaining senior staff for longer will only delay the effects of the ‘retirement bulge’ that will affect the whole profession in the next decade.”

Ofsted found the monitoring, evaluation and development of teaching was a weak spot in the leadership and management of a fifth of schools.

The worst area in secondaries was the governing body’s effectiveness in fulfilling statutory duties, which was unsatisfactory or poor in nearly a third.

Headteachers will face even more rigorous treatment by Ofsted from September when they will be assessed on how much they inspire their staff and pupils and whether they act as good role models.

Leadership and management: What inspection tells us is at www.ofsted.gov.uk. NCSL’s School Leadership Report 2003 will be available at www.ncsl.org.uk from Tuesday