School inspectors in England are going to spell out for parents what staff vacancies schools have and how much they are relying on temporary teachers.

Inspectors from the schools watchdog, Ofsted, already collect the information when they visit schools.

But they are to get new guidance telling them to make the situation much clearer in their reports.

The chief inspector of schools, Mike Tomlinson, said in his annual report earlier this year that too many schools were being forced to depend on temporary staff or teachers without a subject specialism - jeopardising the effort to raise standards.

Now he has decided that, from September, there should be a statement detailing the number of vacancies in a school and the number of posts which are filled by supply staff.

Qualifications count

"We are going to be looking at including in reports a statement from head teachers which gives a position on staffing," he said.

Such information would normally be included in the full version of a school's Ofsted report, where relevant - but not in the summary which schools are obliged to give to parents.

Mr Tomlinson said information about teaching qualifications was also an important factor.

"It isn't qualifications alone. It is qualifications and experience," he said.

"But certainly it is important to know the proportion of lessons, say in science and maths, being taught by someone who doesn't have a good grounding in science and maths."