In the case of teachers, the points scale, known as the 'pay spine', runs from 0 to 17 - in theory anyway. In practice the bulk of teachers start as honours graduates on point 2 and can rise to point 9.

Sarah Cox is a newly-qualified teacher in her first job, at Ocklynge Junior School in Eastbourne, East Sussex. As such, she earns just over £15,000 a year, and is finding it hard to repay her student loans.

Liz Johnson: Feels under-valued

"It's fairly difficult because, being at college for three years, I worked up a £6,000 debt which I'm currently paying off - and a £750 overdraft, which has narrowly gone down but not much," she said.

At the other end of the staffroom, salary-wise, is Liz Johnson. She has been teaching for 25 years and has additional responsibilities as the school's language co-ordinator. She earns just over £23,000 a year.

Long days

Mrs Johnson's weekdays start at 8am and, she reckons, continue for 10 hours. There is often extra work at weekends. Any spare moments in the working day are taken up with marking pupils' work, planning lessons, writing reports and attending meetings.

Lunchtimes are quite likely to be interrupted by unscheduled school business. It all makes her feel the financial rewards are inadequate.

"Not just the work that you do but the kind of job you are doing, and the kind of qualifications you're supposed to have to do that job - you don't feel that you're being paid for your worth," she said.

Unions say that the various extra salary points which in theory teachers can attract for extra responsibilities are often in reality unaffordable for schools.

Headteachers

There are signs that the government might scrap the existing pay scales for headteachers and deputy heads. Currently, a typical primary school headteacher will be on a range from just over £30,200 to just over £31,000.

Secondary heads typically get between about £43,300 and £46,500. In theory, they could be on close to £60,000 but unions reckon that applies to only about 1% of headteachers at the biggest schools.

All teachers would say the job is about more than pay - that they also always need extra resources if they are to educate children effectively. But improved pay would go a long way towards boosting their incentive to teach more effectively.

In a joint submission to the pay review body in September, the unions said large salary rises were needed to attract good candidates to carry out the government's standards agenda.

They noted a fall of 7.4% in applications for post-graduate teaching courses. Technology, maths and modern languages remain shortage subjects despite the fact that they attract study bursaries.

In a separate submission, the National Association of Head Teachers stressed the difficulties schools have in appointing heads and said a 17% rise would be needed to bring heads in line with comparable management posts outside education.