Jon James, 57, was looking forward to changing down a gear last September by becoming a supply teacher. In the summer, the former deputy head had applied to two local authority-run supply agencies and sent off the necessary paperwork for a Criminal Records Bureau check.

Then he waited... And waited... And waited. By early December - five months after his application - he had still heard nothing, and was still unable to get work from the supply agencies until he was given the legal clearance.

Finally, just before Christmas, he was notified that he would receive his paperwork. Mr James, who has taught for 27 years, says he is angered and baffled by the hold-up.

“I didn’t know whether it had been lost, or whether there’s something someone somewhere has said that needs investigating,” he says. “I have no idea - and there was no way I could find out.”

Mr James had decided to step down from the deputy head’s post at Mill Lodge primary school in Solihull at the end of last academic year. He turned to supply teaching to see him through to retirement.

“I found the job of deputy too hectic,” he says. “As I have only got a couple more years to go, I stepped back - I wanted to arrange things so that I could work when I chose to.”

He applied to supply agencies run by Solihull and Birmingham education authorities, completing all the paperwork and returning it by the beginning of July so that he could start work in September.

“I was told that as soon as the documentation was cleared, I would receive a welcome pack,” he says. “I was also told not to expect much during the first couple of weeks as it was always very quiet on the supply front.”

But by the seventh week of term he had still not heard from either agency.

When he queried it, he was told they were awaiting clearance from the Criminal Records Bureau. Following emails and phone calls to the bureau, he was told that his documentation had been with West Midlands Police since July.

Mr James was able to gain some supply through direct contact with a school.

But he estimates the delay has cost him pound;1,860 in lost income. He is angry.

“The CRB should have realised that there’s something wrong here. I’ve just stopped being a deputy head, working for the same authority for 27 years.

Surely it wouldn’t be beyond their ken to get their act together and say this guy checks out.”

A spokeswoman for Birmingham City Council which runs one of the supply agencies, says the usual wait for a CRB check is between four and six weeks. “Sometimes it can be eight weeks and sometimes longer,” she says. “A wait since July is a long time. But it’s not unheard of.”

The Criminal Records Bureau was set up in March 2002, managed for the Home Office by the Capita group, as a one-stop clearance system which pooled information held by the police and the departments of Health and for Education and Skills. It hit the headlines as soon as it started work because teachers and schools faced delays in its vetting system. It subsequently speeded up the process and increased its capacity - it issued its seven millionth disclosure last summer.

In last year’s annual report, the bureau said that for standard disclosures - where checks are within its direct control - it was able to complete 98 per cent of them in two weeks. But for enhanced disclosures, which require an additional check by the police, it could take longer, although most forces met or exceeded their targets.

John Dunn of the Recruitment and Employment Confederation, the body that represents the recruitment industry, says the bureau still lacks consistency in the time taken to process checks.

“Sometimes the checks do come through, sometimes they don’t, so we can’t predict when the check will be cleared,” he says. “We can get a check cleared in three weeks or three months. There’s no uniformity of response.

“And, of course, this is critical, because by the very nature of temporary work, an opportunity is offered and if you’re not in a position to take it, that’s lost income. Likewise, the schools - they have gaps they need filling. They want the teachers they prefer, but might not be able to get those teachers because they are stuck in a queue.”

The Home Office is considering ending the “portability” of Criminal Record Bureau checks. Today supply teachers can use the same CRB check when they move from one agency to another. But, under the new proposals, a new disclosure would have to be obtained (at a cost of pound;29 for the standard version, and pound;34 for an enhanced one) every time they register with a different agency.

John Dunn believes that such a move would add further bureaucracy and further delays. And it would mean schools increasingly missing out on experienced teachers such as Jon James.

“And what a loss,” says Mr Dunn. “If somebody with that experience and calibre to be a deputy head teacher is in a position to help schools out in the classroom, what a stupid loss that is - especially when the Government is spending millions recruiting people at the other end.”

A spokesman for the Criminal Records Bureau said the organisation tries to meet its target of processing 90 per cent of checks within 25 days.

“But some checks do take longer than that because we don’t want to sacrifice accuracy for speed,” he says.

“We are reliant on the police carrying out their part of the check quickly and efficiently. There will always be rare cases like this and we apologise to Mr James for that.”