There could be tens of thousands more teenagers who are not in education, employment or training (Neet) than official statistics suggest, the children’s commissioner has warned.

A report by Dame Rachel de Souza said around 42,000 16- and 17-year-olds were officially classed as studying at college, but were not showing up at least half of the time.

She said they had gone “under the radar” and were “not getting the support that they need”.

The Department for Education (DfE) said it planned to help colleges track attendance and ultimately to gather that data centrally.

Unlike schools, further education and sixth form colleges in England are not required to collect or report attendance data.

Dame Rachel’s report is based on attendance data obtained from 262 college groups in England and says rates are “substantially lower” than in schools.

It suggests that more than half (52.2%) of 16- and 17-year-olds are estimated to be persistently absent by the standards used in schools, meaning they are missing 10% or more of college sessions.

And around 42,000 (5.9%) are severely absent, meaning they are missing at least half of college sessions.

The DfE estimates that 57,000 16- and 17-year-olds in England are Neet, and Dame Rachel’s report argues that these persistently absent teenagers should be considered as “hidden” Neets alongside them.

Dame Rachel told the BBC a range of factors led to teenagers missing college, including part-time work and travel costs, and that some had been largely absent from education since the Covid pandemic.

She said while those juggling part-time employment were likely to miss college every so often, it was those who are “far more vulnerable” who were likely to be severely absent.

She added that it was “shocking” that the DfE did not collect the data as it meant the issue was “ignored”.

“It’s under the radar and these kids are not getting the support that they need,” she said.

Liam Sloan, principal at Bolton College, said not many students missed more than half of classes, but those who were absent often had mental health challenges or part-time jobs.

“Sometimes the student being able to be offered that £30 shift there and then means more… than the potential qualification in six or seven months’ time,” he said.

He said there was a particular issue in English and maths GCSE classes, which students in England are required to study alongside other courses if they don’t have a grade 4 or above.

Attendance rates at the college had improved in recent years though, he said, and this year it has introduced full-time “positive engagement officers” to greet students each morning and contact those who do not show up.

Dame Rachel said she expected the government to respond to her recommendations, including:

Approximately one in eight people aged 16 to 24 are Neet, according to data published by the Office for National Statistics.

In May, the first instalment of a major report by former minister Alan Milburn warned that figure could be one in six within five years, and that the country was “at risk of a lost generation.”

The final instalment is expected to set out recommendations for tackling the problem in the coming weeks.

Dame Rachel’s report describes “hidden” Neets as those enrolled but persistently absent from college, while Milburn’s interim report used it to describe those who are Neet and also not claiming benefits, and are therefore harder to reach.

Cath Sezen, director of education policy at the Association of Colleges, said she agreed with many of the report’s recommendations but said “funding pressures [were] limiting colleges’ ability to provide tailored support”.

“We have called time and time again for increased investment, better integration of support services and a stronger national strategy for employer engagement,” she said.

The DfE said students in further education needed to be prioritised in future reforms to help tackle the Neets crisis.

A spokesperson also said a new stepping-stone qualification would be brought in to reduce the “endless treadmill” of students failing and resitting GCSE maths and English, and that the government would track attendance in colleges and accelerate the rollout of mental health support teams.