Schools could face losing vital support staff, rising class sizes and little improvement to infrastructure as headteachers tighten their belts to handle increasingly strained budgets.

The Department for Education (DfE) says that, in real terms, school funding will be protected, but rising staff costs, inflation and cuts elsewhere have left budgets stretched and spending power decreased.

And though schools are saving where they can to protect frontline education, there are fears it could lead to bigger class sizes, fewer teachers and a slowdown in projects to update tired facilities and outdated technology.

It comes as teaching unions warn that almost £60m could be lost from school budgets in Norfolk and Suffolk by the end of 2020 if the government does not invest more in education.

New figures from the National Union of Teachers (NUT) and Association of Teachers and Lecturers (ATL) estimate that Norfolk school budgets could fall by £36m and £22m in Suffolk from 2015 to 2020.

Eastern Daily Press: Thorpe St Andrew School principal Ian Clayton. PHOTO BY SIMON FINLAYThorpe St Andrew School principal Ian Clayton. PHOTO BY SIMON FINLAY

Their calculations – which the government has called 'fundamentally misleading' – say this could equate to schools receiving an average of £307 less per pupil and a potential loss of 1,584 teachers.

Ian Clayton, headteacher at Thorpe St Andrew School, said inflation, pay scales, changes in national insurance and cuts to the education services grant (ESG) had left schools struggling to make ends meet.

'We are having to look at other ways of saving money that aren't staffing costs,' he said. 'We won't be refreshing computers, decorating buildings or doing refurbishments as quickly as we would like to.'

The union figures say the school could lose about £400,000 from its budget by 2020, a number which Mr Clayton said was 'on the high side', but not far off the mark.

Eastern Daily Press: Bignold Primary headteacher Clare Jones. Picture: ANTONY KELLYBignold Primary headteacher Clare Jones. Picture: ANTONY KELLY (Image: Archant Norfolk 2016)

ATL Norfolk branch and district secretary Bob Groome described the situation schools found themselves in as 'heartbreaking'.

He said he expected class sizes to rise and was regularly called to help schools restructure their workforce as finances tightened. 'For the children that are losing out it is awful,' he said. 'Support staff numbers are likely to decrease and for the children who need that help, it is just heartbreaking – they have one chance to make a good start.'

The worries were echoed by Clare Jones, headteacher at Bignold Primary School in Norwich, who said that as the school system changed, funding grew ever-more complex.

'With cuts in other sectors, such as the NHS, it is schools that are having to mop up the problems,' she said. 'We are here to educate – so my main focuses are having teachers standing in front of pupils and the resources they need to learn. It is the support resources that will have to go first because they are not the bread and butter. But who then is going to provide any of those services? That's what's so worrying.'

The unions' figures – worked out using 2015/16 funding and factoring in proposed ESG cuts and the national funding formula – show that Ormiston Venture Academy, in Gorleston, could be one of the worst affected – with a predicted budget loss of almost £650,000.

A spokesperson for the school said they did not yet know the exact figures, but said the school has 'robust financial planning' in place and would always 'prioritise investment in teaching'.

The data also predicts that budget struggles could see 16 teachers lost at the Notre Dame School in Norwich by 2020. But headteacher Brian Conway said the number was higher than he would predict – though he added that the data served as a good indicator of the challenges faced by schools.

The DfE said school funding was currently at its highest level on record and would be more than £40bn in 2016/17.

Ending the postcode lottery

The government is currently consulting on a shake-up in the way schools are funded.

The national funding formula, which would be introduced in 2018/19, is said to be fairer and would end the postcode lottery of funding, which has seen rural areas including Norfolk and Suffolk left hundreds of pounds out of pocket per pupil compared with their urban counterparts.

But when figures indicating how exactly it would affect schools – should it go ahead – were released in December, many schools said the changes would only mitigate the losses they were already facing.

Clare Jones, who is also the Norfolk branch secretary of the National Association of Head Teachers, said the formula could see her budget drop by roughly £44,000 in the first year.

Use the NUT and ATL's map to see how they predict your school will be affected.

• How is your school being affected by changes? Email lauren.cope@archant.co.uk