The government faces a “now or never moment” to hit its target of recruiting 6,500 new teachers in England by the end of its term, a new report has suggested.

Analysis by the National Foundation of Educational Research (NFER) says unfilled vacancies are at a record high and recruitment into teacher training remains “persistently low.”

All but five secondary subjects missed this year’s recruitment targets for new trainee teachers, which are set by the Department for Education (DfE).

The government says “work has already begun” to reach its target, including investing £233m next year to encourage more trainee teachers into shortage subjects.

The report says more funding will be needed from this summer’s spending review, which decides how much will be allocated to different government departments over the next few years, if the target is going to be met.

During the election campaign, Labour promised “to recruit 6,500 new expert teachers in key subjects” over the course of its five-year parliamentary term, funded by changing the VAT rules for private schools.

At the Commonweal Secondary School, in Swindon, head teacher Chas Drew agrees more needs to be done.

He is hoping there will be no resignations at his school in the next two months.

“March to May is silly season,” he says.

“Anybody who wants to resign to take up a new job or promotion in September has to hand in their notice by the May half term, and you think: ‘Am I going to be stuck with a gap to fill?'”

Over the last few years, the school has had to make some GCSE class sizes slightly bigger in subjects like maths and science, and has had to cut human biology classes entirely.

Mr Drew says the school benefits from its good reputation, and that word of mouth is “the single best recruiter” of new teachers.

Recent bursary changes in some shortage subjects has increased the supply of teachers in some areas. Starting salaries also recently increased to £30,000, while teachers received an average pay rise of 5.5% last year, fully funded by the government.

But recruitment targets are still being missed, the NFER says.

For primary schools, the number of teacher trainees has fallen from 94% of the government’s target last year, to 88% this year, according to DfE figures.

And in secondary schools, though the number of teachers has grown by 3% since 2015, pupil numbers have grown by 15% in the same time – meaning the number of students in class sizes above 30 has increased.

The NFER’s school workforce lead, Jack Worth, says more students are now being taught by unqualified or non-specialist teachers, with the impact felt more acutely by students living in disadvantaged areas.

“The spending review in June is a real now or never moment. Not taking that opportunity will really risk not delivering [on the 6,500 promise] and not having anything to show the electorate at the end of the parliament.”

Mr Worth says “pay increases above average earnings”, reducing teacher workload and bursaries and career retention payments are all important for attracting more teachers.

The NFER report also predicts teacher recruitment in subjects like English will decline slightly next year.

Bethan Harvey is a qualified history teacher, but is currently teaching English full-time due to the demand for more teachers in the subject.

“I thought, ‘I can do this, I did A-level English,'” she says.

Ms Harvey is now doing a part-time masters degree in English to become a specialist in the subject.

Teaching unions have backed the NFER’s recommendation of a fully-funded pay rise for next year, as well as a 6.1% increase over the next two years, in order to retain teachers and attract new ones into the profession.

The government has suggested a 2.8% pay rise for this year and is currently waiting for the review body’s recommendation before making a decision.

The National Education Union is currently balloting members on industrial action over the government’s initial recommendation.

The NFER is also calling for school leaders to consider more flexible working practices, but acknowledges the difficulties of making that happen.

A DfE spokesperson said next year’s £233m of funding is there “to encourage more talented people into the classroom to teach subjects including maths, physics, chemistry and computing”.

On top of last year’s 5.5% pay award, they said schools were also being encouraged to allow staff to work more flexibly to ease teachers’ workloads and improve wellbeing.