The high rate of teachers leaving the profession has helped schools to survive the funding crisis, according to NEU teaching union vice president Robin Bevan.
Mr Bevan was speaking at a Labour party conference fringe event on teacher shortages when he said that schools were saving around £5 billion a year by new teachers leaving the job and therefore not progressing up the pay scales.
He told the meeting, hosted by the Education Policy Institute and Teach First: “There has been a mass casualisation across the profession over the last 10 to 15 years.
“Look at what is happening in terms of the rate of turnover. If teachers didn’t leave after three or four years – work out the additional costs and multiply that by the number of teachers and you have got about £5 billion in savings.”
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Mr Bevan told Tes that 40 per cent of teachers leave within five years and said the high turnover meant that most teachers were now at around points three or four on the main pay scale.
He said: “We would not have managed to get so many schools through the recent funding crisis if it wasn’t for what I referred to as the casualisation of the workforce.”
Mr Bevan, a headteacher, also said the cost of increasing newly qualified starting salaries to £30,000 would cost schools around £1 billion a year, including the cost of levelling up teacher salaries further up the pay scale.
He said: “At the moment a third of the teaching workforce earns below £30,000. People on M2 [main pay scale 2] will have to be moved up by at least £5,000 or they are going to be on less than NQTs.
“One reason this is significant is because if you are promising additional funding and improved pay, then the cost of that pay increase has to be taken out of that increased funding so any claims you are making about reversing [real-terms] cuts are disappearing very rapidly.”
Among panellists at the event was Russell Hobby, chief executive of Teach First who said: "If you get retention right you would not have to recruit as many teachers. It makes much more sense to keep on someone you have trained and developed.”
A Department for Education spokesperson said the “biggest cash boost for a decade,” was about to be handed to schools, adding: “This package will provide all young people with the same opportunities to fulfil their potential and benefit from the education that’s right for them regardless of where they grow up. The Prime Minister is clear that education is one of his main priorities, and we want a system that boosts productivity, improves social mobility and equips children and adults with the knowledge and skills they need to succeed.”