Matt Hancock's criticism of a school that sent an entire year group for coronavirus testing has been branded "disgusting".
The Health Secretary told the public on Wednesday morning not to get coronavirus tests unless they have symptoms in order to stop people having to travel long distances to get tested.
He said that it was "unacceptable" for whole schools, or large parts of schools, to get tested for coronavirus.
But an assistant headteacher at a primary school in Leicestershire said Mr Hancock’s criticism was “disgusting”.
“The Government had months to consider how the return of schools might affect testing capacity and yet nothing has been done about it,” she said.
“Teachers and children, alongside NHS staff and carers, need to be given testing priority.”
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The teacher said her school had already had six members of staff forced to stay at home due to a lack of available testing, out of a total of around 45 – a loss which makes a “huge difference” to their teaching provision.
This had meant that learning support assistants, who were meant to give closer attention to children with special educational needs, were instead having to cover teaching shortages.
“Teachers are putting themselves at risk with no complaint… to give the best life chances by teaching pupils in person in school,” she added.
“Teachers want children in school but the lack of adequate availability for teachers and children not only means that teachers can’t teach their class but children are needlessly missing out on face-to-face lessons.”
Mr Hancock had told BBC Breakfast: “We have seen this quite sharp rise in the last couple of weeks of people without symptoms who don’t have a good reason coming forward to get a test.
“There have been stories of whole schools, or parts of schools, being all sent to get a test – that is not acceptable, that is not an appropriate use of our testing resources.
“I’ve even heard stories of people saying, ‘I’m going on holiday next week therefore I’m going to get a test.’ No – that is not what the testing system is there for.
“We’ve got to be firmer, I’m afraid, with the rules around eligibility for testing.”
Earlier, he defended the test and trace system as "excellent" despite growing criticism.
He said problems have been caused by people without symptoms requesting tests.
Questioned over whether the system was failing, he told Sky News: “I completely reject the accusation, in fact quite the contrary.”
He said the UK has the biggest system per capita in Europe and the highest testing capacity “we’ve ever had”.
“However in the last couple of weeks we’ve seen an increase in demand, including an increase in demand from people who are not eligible for tests, people who don’t have symptoms,” he added.
“We’ve seen an increase of about 25 per cent of people who are coming forward that don’t have symptoms and aren’t eligible.”
The Evening Standard has contacted the Department for Health and Social Care for comment.