Headteachers are beginning to close entire schools due to swelling numbers of Covid-19 cases.
On Thursday, Andy Bryers – headteacher at Framwellgate School in Durham sent every child and teacher home after a dozen cases of the delta variant were reported.
He said: "Unfortunately we have taken the decision to close the school – initially for the rest of this week – due to Covid.
"We currently have 300 students and 8 teachers self-isolating. The delta strain is so virulent with different symptoms. I thought these days were over."
Elsewhere in the north east of England, Lanchester Endowed Parochial Primary School posted on Durham County Council’s website that it would be closed until Monday citing "health and safety issues around increased Covid cases".
St Joseph’s RCVA Primary School, also in Durham County, will be closed until Monday having shut its doors on Tuesday.
In a letter home to parents, the headteacher said: "We have had to closed school due to a rise in the number of positive Covid tests within the school community.
"To ensure we can reopen as safely as possible, we currently have cleaning contractors in school undertaking a deep clean of the whole school."
Seaham Harbour Nursery in the area has also closed after reporting a positive case. It too is scheduled to reopen on Monday.
With cases surging (delta cases can be seen below) and no change in the school bubble system, Mr Bryers said: "We need a better plan for close contacts to avoid closure or disruption next year."
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Media minister John Whittingdale said on Wednesday that adhering to coronavirus measures was not always happening outside of schools.
Asked on BBC Breakfast about the number of pupils missing lessons due to having to self-isolate, Mr Whittingdale said ministers were concerned about the issue but said: "We are still fighting this pandemic."
He said while schools were "very careful" to follow advice such as social distancing, "that doesn’t always happen outside school".
He gave an example in his constituency of Maldon where "a dozen" positive cases were found after a group of students celebrating exam results "didn’t abide by social distancing, they were hugging each other".
Mr Whittingdale said the Department for Education was "incredibly anxious to make sure that children are able to attend school".
He added: "The most important thing is public health and we’re not going to do anything to put that at risk."
Asked whether the Government would look at reducing the size of Covid bubbles to bring down how many students may have to isolate at once, Mr Whittingdale said: "We’re looking at every aspect."