Heads should be punished if they employ “cheap” cover supervisors instead of supply teachers, campaigners said as they marched through central London last week.

Protestors say those qualified to do the job are being frozen out by “hairdressers and butchers”.

Angry supply teachers marched on the General Teaching Council for England (GTC) and the Department for Children, Schools and Families, demanding sanctions for schools which exploit the cover supervisor role and calling for statutory regulation on their use.

The introduction of the “rarely cover” rule - which prevents teachers stepping in regularly for absent colleagues - has increased the need for staff to supervise lessons.

But supply teachers say heads are freezing them out and replacing them with agency and in-house cover supervisors to save money on their wage bill.

They handed a dossier of evidence highlighting their concerns to the GTC and the DCSF.

Many agencies and schools only have cover supervisor work on offer rather than supply teacher roles - for which pay is around 50 per cent more.

A new protest group called Supply Teachers UK is calling for the return of local council supply teacher pools.

Supply Teachers UK founder Lucy Orchard said: “We are not just moaning about a problem that affects supply teachers. We are not heard or respected due to our poor reputation and yet we are highly-trained professionals who have valid proposals to put forward.

“Our colleagues often forget that we are equally as qualified. Now we are united and have a voice we wish to challenge the old perceptions and promote reform within our own industry.

“Our proposed improvements to supply teaching would not only benefit supply teachers; they would improve the service we provide, offering the highest-quality alternative to the class teacher. You can not put costs before standards.”

David Howse, from Worcestershire, turned to supply teaching ten years ago after a 25-year year career in primary schools. Until this year he was employed on an average of four days a week, but since the introduction of the “rarely cover” rule this has fallen to one-and-a-half days - despite being prepared to work at schools within a 50 mile radius.

“Schools employing cover supervisors will erode the standards of education,” he said.

“Gradually, heads will lose the pool of experienced supply teachers who they depend, on often for long periods.”

The only work that Cheryl Thompson, from Brent in west London, can get is as a learning support assistant. “I’ve been offered a cover supervisor job, but I don’t see why I should take that. It’s more work without much more money,” she said.

The pound;6.50-an-hour option

• Davison High in Worthing, West Sussex, is thought to be the first in the country to have introduced cover supervisors, in 1998.
• Preliminary findings from an investigation by The TES show that in some areas schools now employ teams of up to 10 cover supervisors.
• Agencies can charge schools up to pound;150 a day for a supply teacher, while cover supervisors typically earn pound;6.50-pound;7 an hour.
• Guidance from the Training and Development Agency for Schools states that cover supervisors should only be used for “short term” absence, but does not define “short term”.
• The Association of Teachers and Lecturers is campaigning for cover supervisors to be compelled to pass a specially designed national qualification before they can be put in charge of a class.