Ministers are warning that taking just one week’s holiday a year during term time can significantly harm a child’s academic performance.
New research from the Department for Education suggests that children who miss just seven days’ schooling each year see their prospects of gaining five good GCSEs fall dramatically.
Officials have compared the performance of children over the two-year GCSE course, to the number of days taken off, and were concerned at how great a difference short periods of absence appear to make.
The research found that just 31 per cent of children who missed more than 14 days of lessons over two years got the “gold standard” of good grades in English, Maths, Science, a humanities subject and a language.
It compared to 44 per cent of pupils who attended school every day. And just 16.4 per cent of children who miss 28 days of school over two years - the equivalent of two weeks' holiday each year during term time - get five good GCSEs.
An average child will lose three days’ schooling a year due to illness – meaning just an extra week off a year for a family holiday could make a crucial difference.
At primary school, pupils who miss just 14 days of schooling between the age of 7 and 11 are 25 per cent less likely to achieve level five (literacy and numeracy “above expectations” ) than those with no absence.
Education Secretary Nicky Morgan said the figures Support her department's crackdown on parents who take advantage of cheap holiday deals by removing children from school in term time.
Under new rules, headmasters can only grant leave in "exceptional circumstances" and local authorities can impose fines on parents who ignore the rules.
"The myth that pulling a child out of school for a holiday is harmless to their education has been busted by this research. Today heads across the country have been vindicated – missing school can have a lasting effect on a pupil’s life chances."
The DfE conceded that the research does not take into account other factors - such as whether parents who take children out of school in term time are also less strict when it comes to completing homework.
However, they said it supported anecdotal evidence from teachers that pupils struggle to catch up on missed lessons and can be left permanently trailing if they miss just a small portion of the curriculum.
Some parents have campaigned against a new regime of £60 fines on parents who remove children from the classroom. Some 64,000 parents were given the fines last year.
Ministers are unrepentant, however. DfE data shows the absence rate was 4.4 per cent last year, down from 6 per cent in 2010 and the lowest level since records began. It is the equivalent of 800,000 fewer days of school being missed.