More than 35 teachers at a Birmingham school are being escorted during classes because criminal record checks have not been carried out.

Ofsted inspectors ordered the unchecked teachers double up with approved staff at Great Barr School after finding the worrying lapse during an official inspection last month.

The school insisted that pupil safety has never been at risk despite what it described as “an administrative error”.

The school, which with almost 2,500 pupils is Britain’s largest, has also been given notice to improve by the inspectors – although not long ago it was regarded as the best in north Birmingham.

All staff who work with children now need to have clearance from the Criminal Records Bureau confirming there is nothing in their past which suggests they may be a risk.

Local councillor and member of the school’s board of governors Graham Green blamed red tape for the delays.

Coun Green (Cons, Oscott) said: “Many of these people have had police checks with other schools and other organisations but they have to go through the whole process again. The Criminal Records Bureau is overwhelmed. I feel very confident that parents have nothing to worry about.”

He added that the Ofsted notice to improve was not a reflection on management or teachers, but a result of under investment and poor infrastructure.

“It needs some serious investment,” he said.

But chairman of Birmingham City Council’s education scrutiny committee Coun Jon Hunt (Lib Dem, Perry Barr) said that he will be asking for a report on the situation: “It suggests the need for a bit of a shake-up. Such a large school being given notice to improve is a major concern. The scrutiny committee may need to look at the situation closely. It’s disappointing, especially as the other local school Perry Beeches has been the most improved. We want all schools in the area to be successful.”

A statement issued by head teacher Kate Abbott said: “During a recent check of our personnel records, we found that up to date Criminal Records Bureau, or CRB, clearances for a small number of our staff had not been confirmed.  Most of these staff had been CRB cleared by other organisations prior to taking up employment with our school. 

“The necessary documents have been submitted and the up to date clearances will be completed in the next few weeks. Whilst we have absolutely no reason at all to believe that any staff pose any risk to students, we have arranged for our examination invigilators and instructors who have enhanced CRB clearance to be present in class with these colleagues as we await the processing of these documents.”