The High Court has given its backing to schools which refuse to let parents take their children on holidays during term-time.
Schools continue to have the discretion to let pupils out of lessons for up to 10 days a year if the headteacher allows it, and a further 10 days in extreme circumstances.
However, the ruling by two senior judges this week is expected to send a clearer message to parents that term-time breaks are not a privilege they can demand.
Lord Justice Auld, sitting with Mr Justice Sullivan, backed the decision by Bromley council to take legal action against a mother who took her three daughters out of primary school for nine days.
The mother, who cannot be named, took the children on a week's holiday in November 2003 without permission because it was "important for the children's social development" as it involved being in a dancing competition.
She then won a holiday in January 2004 in a competition. Bromley council attempted to prosecute her for her daughters' absences in September last year but she was acquitted by magistrates who said these seemed justified.
However, the High Court judges ruled this week that the London borough should be allowed to appeal against the ruling.
Lord Justice Auld said the case should be sent back to the magistrates with a direction to convict the parent, but also an indication that she should receive an absolute discharge because of the time which had elapsed.
The ruling was welcomed by teachers' unions. Jerry Bartlett, deputy general secretary of the NASUWT, said: "Teachers would probably welcome holidays during term-time, but that would cause disruption in the classroom and extra burdens on other staff."