Police checks on thousands of newly-appointed teachers and school support staff have been completed, allowing them to start work at the beginning of term next month.

But many more checks have still to be completed - with many schools only a week away from opening.

An extra 100 staff were taken on at the Criminal Records Bureau (CRB) who worked through the bank holiday weekend to clear a backlog of applications.

Now almost 4,000 of the most pressing 25,000 applications have been dealt with.

But the National Association of Head Teachers is sceptical about the government's chances of meeting its deadline.

NAHT general secretary David Hart says: "I think it's touch and go."

"Obviously, the government are driving hard and I think we will have to keep our fingers crossed that they will be able to do the necessary by the time schools go back next week."

Short school day

And Eamonn O'Kane, general secretary of the National Association of Schoolmasters Union of Women Teachers, said the extra measures being introduced by the government to clear the backlog may not be sufficient.

This could mean pupils being sent home early as schools struggled to cope with a shortage of staff, he predicted.

"My own view is schools will make alternative arrangements such as getting supply cover and doubling up some classes."

Last week it emerged that the Department for Education has been rushing to get the checks on school staff completed to avoid chaos at the start of the autumn term.

Teachers' and head teachers' unions, as well as teacher supply agencies, have long been warning of a crisis looming with so many checks waiting to be done.

Many head teachers fear they may have to cover for vacancies in September if checks on new members of staff have not been completed.

Compulsory checks

Teachers and other adults who work in schools have to undergo a double clearance before they can work with or near children.

Their names must be checked against List 99, the secret dossier of people convicted or suspected of child abuse.

They must also have checks on criminal records, a process that can take considerable time as they may have worked in several different police force areas, all of which have to be contacted.

The CRB, a Home Office agency, was set up to provide a speedy "one-stop-shop" to deal with both List 99 and criminal record checks, but delays built up almost as soon as it opened in the spring.