There’s never a ­moment when Debby Penton doesn’t know, exactly, where her 12-year-old son Ben is. Whether he is ­arriving at school on his bike, or just about to walk in the front door at the end of the day, she gets a buzz on her Apple Watch from a real-time location-­sharing app called Life360.

“Because the app is geo-fenced, and throws a virtual geographic ­boundary around our house and his school, it alerts me when he crosses it,” says ­Penton, 45, a managing director from Kingston, Surrey. “So when he gets to the end of the road on his way home, I can just go and open the front door, so he doesn’t have to get his key out.

“I loved the idea of The Marauder’s Map in Harry Potter – where you could see the location of everyone in Hogwarts. It’s kind of like a version of that,” adds Penton, who also finds the app useful for keeping tabs on the whole family when they are on holiday.