Teachers will not support being forced to return to the classroom for summer schools, a national education union has said.

But instead a more strategic targeting of children – especially those in younger years should be undertaken to address what the needs are for individual children.

The warning from Jerry Glazier, secretary for National Education Union's (NEU) East Essex district, comes amidst discussions within Government over how to make up for months of lost education due to Covid-19 – including whether to provide funding for catch-up classes over the summer holidays.

At the same time, a new report from the Institute for Fiscal Studies (IFS) looking at the impact of lost schooling on children, is calling for much more money to be spent in order to help pupils catch-up and for "big and radical" ideas on how to do it.

The IFS says that children are likely to lose at least half a year of normal in-person schooling due to Covid-19 – leading to fears that it could affect them for the rest of their lives, causing issues such as higher inequality and lower future pay.

It has suggested several options including extending the school year, lengthening the school day, mass repetition of whole school years or summer schools.

But Mr Glazier warned against forcing teachers back into the classroom over the summer holidays.

He said: "We will look very carefully at what the Government is proposing in terms of funding. But we will not support anything that effectively changes the terms and condition of teachers.

"If teachers decide they want to volunteer to do that in the summer – that is fine, as long as it is genuinely voluntary.

"We have got thousands of supply teachers across the country who aren't being employed at the moment, some are furloughed. And clearly there is a capacity there which could and should be used by paying those staff appropriately to do it.

"The concept of catch up is an important one.

"Clearly we as an education union are concerned about the impact of the pandemic on the most vulnerable kids in schools and obviously we support vulnerable children being in school.

"The issue of ensuring that children are supported in accessing education to counteract the negative impact of Covid is something that needs to be looked at strategically by central government and needs to be supported financially."

Mr Glazier said that even though a supply teacher may not have knowledge of a certain child's education needs, it should not stop that resource being used.

"It is about how you plan in a way that is going to be effective," continued Mr Glazier.

"I think it is inconceivable that anyone would think it is sensible to deny teachers a break at the end of this academic year.

"They need a break to recharge batteries but they also need a break to do what they do every summer holiday and that is to prepare for the new academic year.

"There is a consequence of expecting teachers to carry on working – even on a voluntary basis – and not have a further impact on their capacity to do the job effectively from the start of the autumn term."

The IFS estimates that by February half-term, the total loss in face-to-face schooling time will amount to around half a normal school year for children across the UK.

That is before accounting for lower-than-normal attendance rates in the 2020 autumn term, especially in disadvantaged areas.

If most schools do not go back until after Easter, children will have lost about two-thirds of a normal school year.

The IFS also estimate that given a year of schooling increases people's incomes by eight per cent per year, then someone losing half a year of schooling could lead to £40,000 in lost income over their lifetime.

This in turn is equivalent to £350 billion in lost lifetime earnings across the UK's 8.7 million school children.

The unprecedented nature of the current crisis makes it hard to predict the actual effects but some evidence is already beginning to emerge, the IFS has said.

Despite some of the best digital infrastructure in the world for home learning, the empirical evidence shows that the test scores of Dutch primary school children were significantly lower than previous cohorts.

Mr Glazier added: "What is important is teachers doing a proper analysis of where the learning loss has been and where the gaps are and what is the most effective way in dealing with that.

"It won't be cheap and it will have to be sustained for quite a long period of time.

"If you have identified there has been a gap caused by Covid – which has affected many kids' education for a whole 12 months – then to put it right is going to take quite a long time.

"I think a better way of doing this is targeting resources for kids who need it the most because that will be much more obtainable logistically."

Mr Glazier said that the coronavirus crisis has unveiled how unrobust the education system is but that resource must be targeted primarily at younger cohorts.

He added: "It is crucially important that when schools go back the emphasis is on the younger children – the old Jesuit saying of 'Give me a child until he is seven and I will show you the man' is very true."