A three-year-old boy could have been killed by a nail bomb left by a man who had became obsessed with his mum after she jilted him.
Levigh Dixon found the device in the front garden and played with it before taking it to his mum Joanne.
A 999 operator told her: "Put it outside - do it now, now!"
Neighbour and widower Christopher Dooley, 40, had packed a plastic bottle with nails and gunpowder from fireworks when he discovered Joanne had a new lover.
A court heard Joanne, 34, took pity on Dooley after his wife died, leaving him to care for eight children.
They were lovers for five months, but Dooley, from Ribbleton, Lancashire, became obsessive and put a tracker on her phone.
Dooley wept as he was jailed for three and a half years at Preston Crown Court after he admitted making an explosive.
Joanne criticised the sentence saying: "He could have killed us. It was the hottest day of the year and the sun could have set off the bomb."