A survey of 120 local authorities shows that during the recent national truancy sweeps, two out of three children stopped were found not to be truanting.

The study also found confusion about what counts as truancy.

Terri Dowty, the director of Action on Rights for Children, which carried out the research, said that not only do some authorities record children already excluded from school as truants but also pupils visiting the shops during lunch breaks as well as those arriving late for school.

Ms Dowty said: “Figures are often quoted for the total number of children stopped, implying that they are all truants. This is not true. The majority of children are recorded as being out of school with permissions for legitimate reasons such as medical appointments.”

However, another study by New Philanthropy Capital, a charity set up by banking experts, said at least 70,000 pupils skip school on average every day and two-thirds admit they turn up for registration but skip lessons.

Earlier this year, the National Audit Office revealed that the Government had spent pound;885 million on truancy initiatives over the past six years but failed to cut unauthorised absences.