School leaders have written to the education secretary warning him the education system in England will “grind to a halt” because of a lack of coronavirus testing capacity, The Guardian reports.

Leaders have warned of “partial rolling closures” of schools because staff with suspected Covid-19 cannot return to school because of difficulties getting a test.

Unions representing school leaders said they had been called by at least 400 members who had suspected cases in their schools, just one week after the full return of schools.

School leaders reported having staff off work without symptoms because they shared a house with someone who did – but were unable to get a test.

One leader told The Guardian: “In order to run my school I need to be able to get staff tested quickly and back to work as soon as possible if the test is negative. We will grind to a halt if the availability of tests does not improve rapidly.”

The Worth Less? school funding campaign group, which represents thousands of headteachers across 75 local authorities in England, wrote to education secretary Gavin Williamson to say there was a “significant” threat to schools of partial rolling closures.

Paul Whiteman, the general secretary of the National Association of Head Teachers, said: “The obvious failure of the Covid-19 testing infrastructure puts the sustainable reopening of schools at serious risk and also means that pupils could be missing out on education unnecessarily.”

A government spokesperson said that testing was at the “highest capacity” it had ever been. They stressed that children and staff should only get a test if they display symptoms.