Union bosses have demanded that Boris Johnson provides answers about the risks of infection to staff and pupils of schools staying open.

The NEU teaching union’s joint general secretaries have written to the prime minister after reports that the government may use legal powers to force schools to stay open.

Kevin Courtney and Mary Bousted have called for a full disclosure of the models the government is using to make its decisions.

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Their letter says: “Every day, we are increasingly getting asked why schools aren’t closing if mass gatherings are to be suspended.

“We all want to limit and delay the spread of the coronavirus and we do think medical advice and expert scientific guidance is important in this regard.” 

It adds: “We now see that you may take legal powers to force schools to stay open even when heads and teachers think there is good reason to close.

“In those circumstances, as leaders of the largest education union, we believe it is our right to ask you for fuller disclosure of the models you have looked at and to understand what measures you are targeting.

“It is very important that we understand what the increased rate of infection is for staff and parents if the school remain open, including obviously for staff with underlying health conditions themselves or for those they care for.”

It adds: “We know you’ve expressed concerns about children not in school being cared for by vulnerable elderly grandparents, or by NHS staff who would then not be available for work.

“However, we would suggest that parents and schools would be able to work together to find solutions to that - and we would like to know if you have any modelling of such societal responses.

“Most of all, we think that education staff deserve to have access to modelling of the projected spread of the virus and the projected number of fatalities in a wide variety of scenarios including in scenarios where schools are closed for different periods of time.

“Teachers and other staff would work to help a broader societal response to mitigate the effects of the virus. We know this is especially important in a country where public services, and the NHS in particular, have been run down for so long.

“However, it is vital that you share all of the potential models you have with us if that societal response is to be as strong as possible.”

In a speech to the Association of School and College Leaders union yesterday, education secretary Gavin Williamson said: “The chief medical officer has said the impact of closing schools on children’s education will be substantial, but the benefit to public health would not be.

“The government is particularly mindful of the strain on public services like the NHS that would be caused by key workers having to stay home to look after their children as a result of school closures.

“We will be constantly reassessing this position based on what the chief medical officer and the government chief scientific adviser tell us about whether the evidence would require us to close schools in the best interests of children and the best interests of teachers.”