A BOY of 13 has invented a doorbell that tricks would-be burglars into thinking someone is home – and has signed sales deals worth £250,000.

Laurence Rook's Smart Bell device calls the householder's mobile phone so they can "answer" the caller via an intercom wherever they are.

The teenager, from Whyteleafe, Surrey, got the idea after his mum complained of missing deliveries. Smart Bell will cost £40 on the high street.