Cambridge Education Associates, the private firm which employs external assessors to vet headteachers’ recommendations for the threshold, has agreed to set up an appeals process.

But teachers turned down for the pound;2,000-a-year pay rise still have no recourse to challenge the judgment. Only whole schools will be able to use the process.

The decision marks another Government re-think over the new performance pay system. It follows an extension to the deadline for applications after pressure from unions, and a humiliating defeat in the High Court which ruled the new threshold criteria was introduced illegally.

The Government is now consulting on the criteria through the School Teachers’ Review Body - the route it previously rejected.

The National Association of Schoolmasters Union of Women Teachers welcomed the new complaints procedure which it said followed lengthy negotiations with CEA.Assistant secretary Chris Keates said: “This is not a complete appeals procedure, but it is a step in the right direction.”

The route is most likely to be used by schools where the assessor has overruled the head and turned down several teachers.

A government spokesman said: “A head can lodge a complaint with CEA about the professional conduct of an assessor if they think there is serious concern. But there is no whole-school appeal against an assessor’s findings - it is only for conduct issues.”

The threshold process is currently on pause following the High Court ruling.

The National Union of Teachers, which brought the case, is also calling for an appeals system and wants other unions to join a submission to the STRB. This was dismissed by the NASUWT.

Meanwhile in Wales, Plaid Cymru increased the pressure on education minister Rosemary Butler to stand up for Welsh independence with a call to Mr Blunkett to let the Cardiff assembly make up its own mind on performance pay.