School bubbles and the requirement to self-isolate are “paralysing” society and risk prompting a further lockdown by the back door, a senior government vaccines adviser has said.

Professor Adam Finn, a paediatrics expert and member of the Joint Committee on Vaccination and Immunisation (JCVI), said on Saturday night that ministers either needed to “accept paralysis or relax the rules”.

It follows the launch of The Telegraph’s campaign to scrap the school bubble system, under which dozens of pupils can be sent home if one tests positive.

Figures suggest one in 10 children are currently absent from school, a four-fold increase in just a week, with the proportion closer to 15 per cent in secondary schools.

Campaign for Children: Education: The days lost

Prof Finn said the Government needed to find a “happy medium” between the current state of affairs and doing away with all precautions.

“It’s clear not just in schools but in society more generally that because of the rapid rise in cases and the number of contacts that a lot of areas of activity have been paralysed by the need to isolate.

“So there’s an emerging dilemma there that either you accept that kind of paralysis or you relax the rules.

“At some point, whether it’s schools or workplaces, we’re going to have a kind of de facto lockdown, simply because so many people are being asked to self-isolate.”

Prof Finn said the threat to children from Covid-19 was “primarily through disruption to their development and education”.

It comes amid reports the Government is working up proposals to ditch bubbles from July 19, and to replace the requirement for pupils who have come into contact with someone who tests positive for Covid with a system of daily tests from the autumn term.

Campaign for children (Day 5)

Meanwhile, the government’s Scientific Advisory Group for Emergencies (Sage) is understood to have discussed the use of air purifiers in classrooms in a bid to make schools more Covid secure after the summer.

New York has recently announced an intention to have two machines in every classroom from September.

The British Medical Association on Saturday called for more effective public messaging about the benefits of ventilation in fighting Covid.

Prof Finn said that while children had little to fear from the virus itself, scrapping all the current rules could cause an “overreaction” further down the line if cases in schools went up.

Gavin Williamson, the Education Secretary, said on Wednesday that the Government expected to confirm plans to end bubbles as part of Step 4 of the roadmap, expected on July 18.

Asked about plans to install air purifiers, a Department for Education source said: “Any and all measures relating to the lifting of restrictions for Step 4 are being considered.”