One of the great scandals of the lockdown era was what seemed to be an indifference to the plight of children and the dreadful challenges they faced as a result of draconian restrictions on schools.

Throughout the pandemic, teaching unions clamoured for more rules, and complained if they were relaxed. They were not alone. Polls frequently suggested that tough measures to reduce infection by targeting pupils – even though they showed very little vulnerability to the virus – were popular. Warnings about domestic abuse, compromised life chances and a disastrous impact on social mobility too often fell on deaf ears. However, a storm is brewing that will make it impossible for anybody to ignore the plight of the lost children of lockdown.

The release on Tuesday of official statistics on truancy revealed that 12.6 per cent of pupils are absent from school. To put that into context, it means there are tens of thousands of absent pupils in this country. Around 40 per cent of those are off school for Covid-related reasons such as a positive test or having been sent home after an outbreak. The rest, a significant 7.5 per cent of all school children, are truants. This is a serious rise over the course of the pandemic, from a level of 4.7 per cent recorded in 2018/19.

One of the least discussed aspects of school closures has been the way in which it bred a profound sense of detachment among pupils. These young guinea pigs were left disconnected from the setting and the people most familiar to them – their school and their teachers. It comes as no surprise that many are still staying away.

Persistent absence will have a profound impact. The child who has the good luck of being born into a middle-class family, where professional parents could work from home, is unlikely to be one of the thousands staying away from school. The chances are that their low-income classmates – who are more likely to have had patchy or non-existent online learning during the pandemic – will make up the bulk of the young truants.

Yet these are the pupils who need school most. Education remains the best route to social mobility, with teachers representing a rare role model of working life to children who grow up in families that have experienced generations of unemployment. When these children don’t meet anyone who inspires them to strive, they lose stimulation and, crucially, self-esteem.

Skipping school is also often the first step on a child’s trajectory to trouble: feeling aimless and hostile to the routine and discipline that animate their classmates, the truant often seeks gangs that offer them a sense of belonging, as well as status. The criminals running these gangs will shamelessly exploit their young recruits: the spike in county lines during the pandemic attests to this new manipulation of adolescents (or younger) who have become loosened from their moorings.

School offers the kind of supervision that youngsters whose parents are both out working all hours to put food on the table lack.

It is enormously difficult for children, once they have entered a spiral of criminality, to escape it. The long-term consequence of truancy today is dangerously likely to be a surge in crime and anti-social behaviour that disfigures the whole of our society tomorrow.

Much of the damage has been done, but there are two changes the Government should make. First, giving 14 to 16-year-old students the choice to opt for technical vocational qualifications would help to entice those who are not academic back into the supportive, structured environment of the classroom.

Secondly, schools should do more to engage parents and to encourage them to feel that school is part of their family’s lives. Not every parent will cooperate, but many – especially those who see their child at risk of slipping into a life of crime – will.

Children have carried too great a burden during the pandemic. They need us to make a concerted effort to win them back – for everyone’s good.

Cristina Odone is head of the family policy unit at the Centre for Social Justice