Amelie Epstein Bowman was in the garden of her grandparents’ Whetstone home when she heard an elderly man in distress calling for help.
The seven-year-old Wolfson Hillel Primary pupil convinced her mum Suzanne to go next door to check, where she discovered Reg Davey, 94, who had been lying on the ground for more than three hours after falling while gardening.
The Second World War veteran had attempted to attract attention by using a whistle hung around his neck.
Her mother helped Mr Davey up and into a chair before calling paramedics.