Children and parents face a month of summer camp chaos despite an official study showing that forcing schoolchildren to self-isolate was unnecessary.
Ministers have been urged to scrap the policy forcing healthy children to isolate immediately, in time to "rescue" summer camps.
The study by the University of Oxford suggested that forcing hundreds of thousands of schoolchildren to self-isolate because a classmate had Covid was needless because daily testing would have been as effective.
The results emerged on the last day of term for most schools, when more than one million pupils are off because of the virus and after months of disruption to education.
Since June, The Telegraph has been running a campaign calling on ministers to put children first as the country recovers from its Covid lockdowns, with action to bring an end to the chaos in schools.
The Oxford study found that 98.4 per cent of children who were sent home for 10 days never went on to develop Covid.
Schools which tested pupils daily instead of requiring them to self-isolate saw four per cent fewer cases, which experts said may be because infected youngsters were more open about their contacts when the consequences were not so severe, meaning cases were identified more quickly.
Anita Grant, the chairman of Play England, said keeping the self-isolation policy in place would be a "massive problem" for summer camps over the coming weeks.
"The big issue with the holiday activities is that children are running around and there is no way of clarifying who they were close to," she added. "There is a very real possibility that summer camps, activities and play groups will just shut down for the full 10 days if someone tests positive."
The Government has said that from August 16, children, as well as fully-vaccinated adults, will no longer need to self-isolate following close contact with someone who tested positive. Instead, they will be contacted by NHS Track and Trace and advised to take a PCR test.
Ms Grant, also the chief executive of the Islington Play Association, said it was "only fair" to end isolation for children now rather than wait until next month.
"We have literally just got a report saying that children didn’t have to self-isolate," she said. "They just spent a term doing it, but now they have to do it in the summer holidays as well? It just seems bizarre."
Molly Kingsley, the co-founder of parent campaign group UsForThem, said it was "utterly ridiculous" to keep the self-isolation policy in place for children over the next few weeks given the study’s results.
"Given what we know of the harm caused by isolation for healthy children, but particularly in light of the study, surely the only fair course of action is to ditch isolation today, now, in time to rescue summer camps," she said. "Why do we keep imposing policies on children which are really detrimental for their health and well-being? Let’s be bold enough to change course and do the right thing by children."
Ms Kingsley said sending children home from summer camps would have a “hugely detrimental impact” on their mental and physical health and be disruptive for working parents who rely on the camps for childcare.
A government spokesman said: "Throughout the pandemic, we have followed scientific and medical advice, putting in place protective measures such as self-isolation following contact with infection to keep our schools and wider communities safe, while prioritising students’ attendance at school and college because of the benefits of face-to-face education for development and well-being."
Robert Halfon, the Tory chairman of the education select committee, also urged ministers to end the isolation policy for children as soon as possible, saying: "School summer activities programmes have got to go ahead without disruption and without isolating healthy children."