But this wasn’t a school trip. Jason, eight, and his sister Sarah, 13, went with their dad at the beginning of September last year. They’d just had six weeks’ school holidays but Dad, a single parent, wanted to give the kids a treat and preferred to avoid the August tourists. This term they took another day off to celebrate Dad’s birthday at McDonald’s. Both are bright children who talk about high-powered careers - Jason wants to be a vet - but they miss so much school it will be a miracle if they realise their full potential. Their father’s behaviour may be misguided and irresponsible - but is he a criminal? Yet if he persists he might end up in jail like Patricia Amos, now serving 60 days in HMP Holloway for allowing her teenage daughters to truant.

Truancy is tragic, with five million school days being lost each year. In my 25 years of teaching there was nothing I found more frustrating. Twenty years ago, I worked with persistent truants in pupil-referral units and only then began to understand what a complex issue truancy is. As a home tutor when “school refusers” were eligible for two hours’ home tuition every day, I got to know truants’ families very well. Most were at their wits’ end after months, sometimes years, of conflict with their offspring. Single parents would deliver their children to the school gates before work, but within half an hour the kids would be back at home or on the streets with their mates, and many were already in trouble with the police. As sole breadwinners these parents were under enough stress and the idea of jailing them appals me.

Truancy must be tackled by looking at its root causes. Ten years ago I undertook research to examine links between educational failure and criminal offending. I asked 250 serving prisoners in 12 jails whether anything could have been done at school - or at home - to prevent their ending up in custody. Nearly half said they had truanted regularly. Some blamed family break-up, chaotic parental relationships, multiple house moves which fragmented their schooling, physical and sexual abuse and long periods in care. But far more blamed boredom at school, the irrelevance of lessons and feeling lost in very large classes where teachers had no time to recognise them as individuals with their own special talents and difficulties. More than half said they did not think anyone checked whether they were at school or not. I note that newspaper reports on the Amos case quote the truants’ headteacher as saying that she did not know the girls personally as it was a very big school.

Prison reform groups estimate that the prosecution and jailing of Patricia Amos will cost the taxpayer pound;10,000. The Government feels this is money well spent. Education Secretary Estelle Morris has hailed the landmark ruling as a success because the two girls are now back at their desks. But at what a terrible price for the family? Like two-thirds of the women prisoners I interviewed for a study of female incarceration, Amos was shocked to get a custodial sentence and had made no preparations for child care. She was so distressed that she had to be admitted to the prison hospital. What bitter legacy will her children inherit from all this? They are now publicly stigmatised as cruelly as if they had been put in the stocks and pelted with rotten tomatoes.

The way to combat truancy is not to criminalise parents but to offer children an education they don’t want to miss. Ways have to be found to involve parents like Mrs Amos and Jason’s dad so that they feel part of the home-school partnership without which few children will succeed. The money spent on prosecutions and imprisonment would be better used for proper resourcing of schools, on cutting class sizes and on extending imaginative schemes like the education maintenance allowance which offers grants of up to pound;30 a week to persuade deprived youngsters to stay on in education.

Carrots generally work better than sticks.

Angela Devlin’s latest book Cell Mates, Soul Mates: stories of prison relationships is published by Waterside Press, Winchester.