A record number of penalty notices were issued to parents for withdrawing their children from school in Gloucestershire to go on holiday last year, new figures show.
Penalty notices are handed to a guardian if a child frequently misses school and costs either £60 if paid within 21 days of receipt or £120 thereafter.
If it is not paid in four weeks, the local authority must either prosecute or withdraw the notice.
The National Association of Head Teachers said these fines are "too blunt" and are becoming ineffective.
Department for Education figures show Gloucestershire County Council handed out 1,842 penalties to parents and guardians for their child's persistent absence in the 2022-23 academic year.
Of them, 1,835 (100%) were issued due to students being taken out of school for holidays – up from 702 the year before, and the highest on record since 2016-17.
Before the pandemic in 2018-19, 1,612 penalty notices were issued for unauthorised holidays.
Paul Whiteman, general secretary of NAHT, said: "Fines have always been too blunt an instrument when it comes to tackling persistent absenteeism.
"The use of fines is controversial, and it is becoming clear that they are ineffective in addressing overall absence."
He added: "Unless more is done to find out the reasons behind continual periods of absence and tackle the root causes behind persistent absenteeism, including support for vulnerable families and for children and young people’s mental health, fining families is unlikely to solve the issue."
Across England, nearly 399,000 fines were issued in 2022-23 – a 20% jump from pre-pandemic figures.
About 356,000 (89%) were for unauthorised holidays, as families looked to book cheaper vacations outside school term times.
It has more than trebled since 2016-17, when 116,000 such fines were imposed.
A Department for Education spokesperson said: "We know that regular school attendance is vital for a child’s education, wellbeing and future life chances."
They added: "Parents have a duty to make sure their child regularly attends school, and holidays should be around school breaks to avoid taking children out of school during term time.
"Our guidance is based on a support-first ethos, however we support schools and local authorities to use punitive measures such as fines where it is deemed appropriate."