Section 444 of the Education Act 2006 (the Act) states that a parent is guilty of a criminal offence if his or her child fails to attend school "regularly". A child will not be deemed to have failed to attend regularly if, among other things, the school granted leave for the periods of absence.

M attended a maintained primary school in the Isle of Wight. Her father (Platt) was no longer married to M's mother; the living arrangements for M were split between the two parents on a 50:50 basis. The mother took M on an unauthorised term-time holiday in February 2015, resulting in M missing 10 sessions. Platt was not involved in the decision to take M on this holiday. He took her on holiday in April 2015, resulting in her missing 14 sessions. Platt had applied to the school for leave, but been refused, with the school warning him that a fixed penalty would be issued if he removed M from school and took her on holiday in April.

The holiday went ahead.

Proceedings were brought against Platt in July 2015, and the case was heard in the Magistrates' Court. According to the evidence, up to the time Platt took M on holiday, her attendance rate during the academic year was 95%; at the end of the holiday it was 90.3%. The holiday request form completed by Platt said that 90-95% attendance was acceptable.

In deciding whether Platt had committed an offence, the Magistrates' Court did not take account of the holiday in February, since he was not responsible for that absence. It ruled that there was no case to answer, on the basis that M's attendance had never slipped below 90%, and the document supplied by the school itself stated that this level of attendance was acceptable.

The Magistrates asked the High Court to determine whether they had made a mistake by including M's attendance outside the unauthorised holiday period in April when calculating the percentage of M's attendance.

The High Court considered an earlier case on the same issue, in which the Court had found that the question of whether a pupil has attended school regularly will be a question of fact and degree, and that it does not automatically follow that there has not been regular attendance merely because the pupil has taken an unauthorised holiday.

The High Court took the view that this was a reasonable approach. Although an unauthorised holiday might constitute an offence, it would need to be considered in the context of the surrounding circumstances, including the pupil's attendance over a longer period than the unauthorised absence. The Magistrates had been right to have regard to the wider picture and their conclusion was one that was reasonably open to them.

The judgment ends with the Court mentioning Platt's observation that, because the Act does not define "regular" attendance, it is impossible for parents to know whether or not they will be committing an offence if they take their children on holiday in term-time without the school's blessing. The Court found that it was unnecessary to consider this issue to deal with the case, but added that, had it been necessary, "we should have had to consider whether the Department for Education should be served as an interested party in order that it might have the opportunity to make submissions on these wider issues".

This case has chiefly been of interest to parents, anxious that their holiday plans might gain them a criminal record. However, it raises questions about how schools should handle requests for authorisation to take pupils on holiday during term-time.

For maintained schools, the position on absences is set out in law: they should not be authorised unless (a) an application has been made to the school in advance by a parent with whom the pupil normally resides; and (b) the school considers that leave of absence should be granted due to the exceptional circumstances relating to that application. This provision does not apply to independent schools, but many treat it as a benchmark and formulate their policies accordingly. Unfortunately, like the offence in section 444 of the Act, it lacks certainty, and the DfE's guidance does little to clarify it.

In this case, the school's policy was that attendance above 90% was acceptable. The Magistrates' Court chose to treat this as an appropriate benchmark and the High Court deemed their decision to be reasonable. That does not make 90% a reliable guideline in all cases, but it is a factor that independent schools might bear in mind when considering their own policies. Ultimately, their legal duty is to comply with the independent school standards, and to ensure that any policy on granting leave does not compromise their ability to deliver an education that meets their requirements.