Schools have been overwhelmed with a tide of requests from parents who say they are key workers, headteachers have warned.
The "vagueness" in the government's key workers' list has "increased the risk of school staff getting the virus" – as too many parents are asking teachers to care for their children, according to primary school leaders.
Education secretary Gavin Williamson said last night on Twitter: "You should only send your child to school on Monday if you have to, because your work is critical to our Covid-19 response.
"If you are able to keep your child at home, you should."
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But teachers have said they are still experiencing a tide of requests from parents claiming to be key workers, due to ambiguities in the government's list.
Replying to Mr Williamson's tweet, one teacher said: "We need further clarification from the government. This has been a nightmare to organise and is open to people taking advantage."
Another said: "If you’re not too busy on Monday Gavin, would you mind ringing the stay-at-home mum who thinks her children should be able to come to school because her husband is a key worker?
"I’d do it but I’ll be busy looking after the children whose parents are ignoring your plea. Ta".
A third teacher added: "I've got one coming in on Monday because his Mum is a nurse and his Dad, who doesn't work, will be too busy starting to fit the new family kitchen. Could you phone her too, Gavin?"
And many primary school leaders have shared similar stories on Facebook.
Asked to share the "most strange/ridiculous" key worker jobs suggested by parents, leaders said they had dealt with requests from a nail technician, a tanning shop worker and a tree surgeon.
Jon Le Fevre, headteacher at a primary school in Hampshire, told Tes: "The whole point of reducing the school population to very few numbers has been a real struggle for heads, [especially] as now [children can be sent to school] if only one parent [is] a key worker.
"The vagueness simply has put too many children in school, increased the risk of school staff getting the virus...increased the risk of others getting the virus and put unnecessary strain on the NHS which is the complete opposite of what closing schools was meant to do."
Schools are now closed to all but the children of key workers and vulnerable pupils.
A list identifying these key workers was published by the government just before midnight on Thursday.
It includes doctors, nurses, care workers, teachers, people responsible for the management of the deceased and journalists working for public service broadcasting.