I only have anecdotal evidence on Covid19 positive test results in Brent secondary schools so have put in an FYI request to Brent Council for actual statistics.
This is the National Education Union statement released on Friday:
We are pleased that SAGE has recognised the important role that schools and school-age children play in transmission of the virus . We have been concerned for some time that an erroneous belief that children do not play a significant role in the transmission of coronavirus was badly distorting policy. This is in spite of a clear and sharp trend in infection rates among secondary school pupils in particular since the start of term.We call on the Government to play a much more active role to suppress the transmission of COVID within schools. Schools have gone to great lengths to make themselves as safe as possible but there is only so much they can do on their own. We put forward a ten-point plan in June with suggestions including hiring additional space and teachers to reduce class sizes. More recently we have put forward ideas to enable social distancing in schools through the use of rotas for older secondary school pupils. All these suggestions were ignored. Schools have been given inadequate advice - more often than not delivered at the last minute - and with no additional funding.The situation is untenable and widespread disruption will continue unless the Government takes steps to get coronavirus under control in schools.