As we reach the 20th anniversary of the magical British blockbusters, the real magic lies in the way its young stars have stayed on the rails – unlike many before them

There are many magical things about the Harry Potter film series, which marks its 20th anniversary this month with a re-release of Harry Potter and the Philosopher’s Stone. Perhaps the most miraculous one, though, is that its three stars – Daniel Radcliffe, Emma Watson and Rupert Grint – are still alive, apparently content, and not noticeably addicted to class A drugs.

Each continued acting, occasionally even starring in bona fide hits: Radcliffe in The Woman in Black; Watson, who is also a UN women goodwill ambassador, in Beauty and the Beast. Grint, star of the M Night Shyamalan series Servant, also became a father last year – his partner is another former child actor, Georgia Groome of Angus, Thongs and Perfect Snogging – and celebrated by joining Instagram. Even there, he has shown a characteristic level-headedness by posting a mere six times in 11 months.