The teacher recruitment crisis will only be improved by a double digit salary increase, the profession's biggest union has warned.

In its submission to the School Teachers' Review Body the NUT warns that nearly half the full time teaching force will have retired over the next 20 years, mainly due to the low starting salaries causing graduates to look for alternative careers.

The pay demand comes just 48 hours after chancellor Gordon Brown called for pay restraint in the public sector.

At present, a teacher's starting salary is 12.1 per cent below the average graduate income.

After three years in post this gap widens to 23.4 per cent, the union claims.

Nearly 60 per cent of teachers are over the age of 40, warns the NUT.

"The government persists in claiming that recruitment to the profession is buoyant," said general secretary Doug McAvoy.

"The claim is false. A 32 per cent increase in applications to teacher training last year declined to a 10 per cent increase in acceptances.

"Don't be blinded by percentages. The 23 per cent increase in applicants to train as physics teachers was just 80 people.

"In German the 28 per cent increase was only 73 people. Our children deserve better than the short-term approach this government adopts.

"The government is trying to get round the problems on the cheap. It wants to use unqualified support staff to replace teachers. That approach won't deliver its high standards agenda. Three-year imposed awards will make matters worse since they are linked with inflation.

"The review body must live up to its responsibilities and recommend changes that really will recruit, retain and motivate teachers.

"It should tell the government what is needed, not what it wants to hear."