Signs in the area warn against unauthorised swimming (Picture: John Dunne)A 14-year-old schoolboy has died after he jumped into the River Thames as temperatures soared above 30C. ‘My deepest condolences, thoughts and prayers are with his family, friends, teammates and all those affected by this devastating loss. Locals said the boy was one of a group who had been using the area to cool off during the heatwave. Signage in the area stresses that ‘no unauthorised swimming’ is permitted, while another sign warns of ‘deep water’. Detective Superintendent Oliver Richter said: ‘Our thoughts remain with the family and loved ones of this young boy at this incredibly difficult time.