Government figures obtained from shadow education secretary Damian Green, show that truancy in Surrey's secondary schools rocketed from 4,451 to 9,619 between 1997 and 2002.
But a Surrey County Council spokesman said electronic registration of pupils means that more absences are picked up. Coupled with Ofsted's guidance that teachers record pupils' term-time holidays as "unauthorised absences", it means truancy figures swell.
The attendance-recording changes do not explain the massive increase in Surrey truancy, compared with more modest increases in comparable local education authorities who will have been subject to the same changes. The average national increase is only 25 per cent.
But Heath End headteacher David Hoggins agreed that the counting measures were probably to blame.
"Our unauthorised absence figure is quite low, below average I believe. We're fairly tight on absences and we say that unless children attend 85 per cent of the time we won't pay for them to enter their exams."
Mr Hoggins added that many of the school's truants take time off to revise for GCSE exams.
Elizabeth Lutzeier, headteacher of All Hallows School, said truancy is not a big problem but parents taking their children out of schools for holidays is. "Out of 1,300 pupils only five caused us concern last year and that represents a broad range, with one or two long-term truants and the rest being one-off cases.
"What is of much greater concern is parents who take their children on holidays in term time. We say we don't allow it but parents still take it.
"I would like more serious action to be taken against the parents and some travel agents appear to be telling parents their children are entitled to 10 days off a year, but that's only if the school says so."
Weydon School headteacher Lynne Jackson estimated that the number of her pupils truanting is "minimal".
Mrs Jackson records all term-time holidays as unauthorised absences. Those figures go back to the government and contribute to the truancy figures. "What the government calls truancy isn't what we think of as truancy. Truancy's a very emotive word," she said.