Covid disruption gets worse for secondary schools
The latest attendance figures show 22% of secondary pupils were missing, based on who was in school last Thursday - compared with 17% the previous week.
There was another increase in secondary schools sending home pupils - up to 73% from 64% the week before.
The Department for Education says keeping schools open is a "priority".
'Collapse' in attendance
The rising number of pupils being sent home had become a "collapse" in attendance, said the biggest teachers' union, the National Education Union, with almost 900,000 pupils out of school because of Covid incidents.
Geoff Barton, leader of the ASCL head teachers' union, backed the principle of keeping schools open, but said it was time for schools to be allowed to operate rota systems.
"The reality behind these figures is that many schools are experiencing disruption on a monumental scale and are desperately trying to cling on to the end of term," said the heads' leader.
Overall attendance is down to 83% of pupils, below 86% in the previous week - and below the starting point of 88% when schools re-opened in September.
But the fall in attendance is particularly concentrated in secondary schools, with 78% in class last Thursday - and almost three quarters of secondary schools sent one or more pupils home.
Across both primary and secondary schools, the figures show about one in 10 pupils were out of school because of Covid-related concerns.
The great majority of pupils being sent home are because of potential contacts - rather than pupils having caught coronavirus, with only 0.2% of pupils recorded as confirmed cases.
Primary schools have so far been less disrupted, with 87% of pupils attending - but the number of schools sending home one more pupils has risen to 29%, compared with 22% the week before.