A body has been pulled from a river in the hunt for a 12-year-old boy - after four other young people lost their lives in a spate of heatwave tragedies.Tuesday saw the hottest day in May on record as temperatures reached 35.1C at Kew Gardens in London.While thousands of Brits flocked to beaches and popular swimming spots over the long weekend, six people lost their lives after getting into trouble in the water.Police have now confirmed a body was recovered from the River Ribble in Lancashire this evening - believed to be that of a missing 12-year-old boy who got into difficulty while swimming with friends.One man, in his 60s, also suffered a 'cardiac arrest in the sea' after heroically trying to help two relatives who got into difficulty in the water at Tregirls Beach, near Padstow, at around 3.50pm on Monday. The family members were brought to safety by members of the public, before the man was pronounced dead at the scene. Four teenagers also died in separate water-related incidents in the UK over the weekend. The deaths of three boys and a girl were confirmed by police forces in Lincolnshire, West and South Yorkshire, as well as Warwickshire. Reco Puttock, 13, died in hospital after being pulled from the water at a popular swimming spot in Halifax, West Yorkshire, at around 3.20pm on Monday.The teenager was rushed to hospital but sadly died despite the efforts of paramedics.Just hours later, the body of a girl, believed to be 16, was recovered from a lake at a country park in Warwickshire. Reco Puttock was rushed to hospital after being pulled from Leadbeater Dam in Halifax The deaths came a day after 15-year-old Declan Sawyer drowned at Swanholme Lakes in Lincoln Abbie Carmody-Pepper, 15, vanished at Burrow Beach in a separate incident outside the UK in Howth, Dublin, with friends after entering the water