A body has been found in the search for a missing 11-year-old boy who went swimming in a river during last week's record-breaking heatwave.Mackenzie Swift was last seen entering the River Don, near Mexborough, South Yorkshire, on Saturday evening.After he failed to emerge from the water, a 48-hour search operation was launched including firefighters, mountain rescue and an underwater search team. Today, South Yorkshire Police announced they had recovered a body.Chief Superintendent Pete Thorp, district commander for Doncaster, said: 'First and foremost, on behalf of all who have been involved in the operation to find Mackenzie since Saturday, I send deepest sympathies to his family and friends.'Losing a child is every parent's worst nightmare and I know the impact this news will have on the wider community and particularly Mackenzie's school.'I would also like to thank the local community, who enabled us to conduct our search and recovery with very few onlookers and cameras to give Mackenzie and his family the dignity they deserve.'Not only for that, but also for the offers of assistance – we knew we had many members of the public willing to do anything they could to help.' Mackenzie Swift, 11, was last seen entering the River Don, near Mexborough, South Yorkshire, on Saturday evening. Today, a body has been recovered from the water Officers worked alongside partner agencies including South Yorkshire Fire and Rescue service, Woodhead Mountain Rescue, and an underwater search team, as prt of efforts to locate Mackenzie As Britain basked in its hottest May weather in history, the country saw an alarming number of deaths in open-water.In total, since the start of the heatwave last week, there have been 17 deaths. News that police had recovered Mackenzie's body came after a 13-year-old girl was pulled from the River Wharfe in Burnsall, near Skipton, North Yorkshire, on Sunday evening. The teenager was airlifted to hospital where she was pronounced dead, North Yorkshire Police said. The family of Greg Howes, who died in the Norfolk Broads on Saturday afternoon, have urged people to take care on the water.In a tribute, his family said he had been 'dearly loved by his family and loved spending time on the Norfolk Broads'.'At this sad time, his family would like to urge the public to take care and consider their safety when taking part in activities on the water on the Broads,' the statement added.Yesterday, the first picture of a 16-year-old girl who died after getting into difficulty in open water was released. Lillianna Tomlinson 'brought laughter, friendship, and joy to so many', her best friend's mother said The body of 44-year-old Greg Howes was found on Saturday, following an overnight searchLillianna Tomlinson died after entering the River Tame close to Kingsbury Water Park in north Warwickshire last Monday.Her 'devastated' family paid tribute to her in a statement released through Warwickshire Police today.The family said: 'We're deeply saddened to be writing that Lillianna's life has been taken in the most tragic way.'Our family is completely devastated and will be forever heartbroken.'We would like to take a moment to sincerely thank our community for the love, compassion and support that has been shown to us, and for sharing in our grief - it means more than words can express.'An online fundraiser set up by the mother of Lillianna's best friend describes the teenager as 'a bright, kind, and caring young girl who touched the lives of everyone who knew her.'On Sunday, a 13-year-old girl died after being pulled out of the River Wharfe in the Yorkshire Dales National Park.And on Saturday, a woman died after entering the sea to try to rescue her dog in Thornton Cleveleys, Lancashire. Chiedza Nyanjowa, 15, died the day before the girl in the River Wharf Muhammad Secka, 16, drowned while swimming in open water during the heatwave Junior Slater, 12, and Declan Sawyer, 15, both died while swimming in open water during this month's heatwaveThe woman and a man, both in their 60s, were pulled from the ocean near Fleetwood Beach Café by the coastguard before being handed to paramedics.Tragically, the woman was pronounced dead in hospital while the man remains in a critical condition. The dog was 'recovered safe and well'.Last Friday, Police Scotland named a 16-year-old who died after getting into difficulty in the water in Stirlingshire as Charlie Noble.And last Wednesday, the body of 14-year-old Baltazar L'Qui was found in the River Thames, while another teenage boy was found in a pond in Swanscombe, Kent.The same day, a missing teenage boy's body was found in a lake near Blackwater in Hampshire after he went missing while swimming.A body was also found at Hawley Lake in Hampshire after he went missing while swimming. Formal identification has yet to take place, but his family has been informed.Last Tuesday, two boys were found dead, including 17-year-old David Junior-Tita from Crewe, who died at Pickmere Lake in Cheshire.Junior Slater, 12, also died after getting into difficulty in the River Ribble in Lancashire.Phil Crow, 68, suffered a 'cardiac arrest in the sea' while bravely trying to help two relatives who got into difficulty in the water at Tregirls Beach on Monday Reco Puttock was rushed to hospital after being pulled from Leadbeater Dam in Halifax That day, police also recovered the body of a drowned 16-year-old boy from Sheffield who died in a Rotherham lake after going missing while swimming.Muhammad Secka, who had drowned the previous day, was described as a 'lovely, kind boy' who dreamed of becoming a doctor.A 15-year-old girl also died in hospital on Saturday after getting into difficulty in the sea off the coast of Merseyside on Bank Holiday Monday.Chiedza Nyanjowa, from Cheshire, was taken to Alder Hey Children's Hospital after swimming at Formby beach, Merseyside Police said.There were four more deaths on Monday as temperatures reached 34.8C at Kew Gardens and broke the record for the hottest-ever May day.Among them was 13-year-old Reco Puttock, who was pronounced dead after being found in Leadbeater Dam in Halifax, West Yorkshire.Heroic grandfather Phil Crow, 68, also died after suffering a cardiac arrest when he ran out to the sea trying to rescue his wife and granddaughter when they got into difficulty at Tregirls Beach in Padstow, Cornwall.Last Sunday, an unnamed 72-year-old woman died off West Angle Beach in Pembrokeshire. In Lincoln that day, 15-year-old Declan Sawyer also died after getting into difficulty at Swanholme Lakes.The body of 66-year-old Stephen Faulkner was found in Tonypandy, Rhondda Cynon Taf on Thursday, following a five-day search.A 19-year-old man, who had been at the lake with friends, was recovered from the water at Balderton Lake, off Heron Way in New Balderton, on Thursday afternoon. Baltazar L'Quy tragically passed away on Wednesday in the River Thames in Oxford Pictured: Charlie Noble - the 16-year-old who died at Bracklinn Falls near the Scottish town of Callander, in StirlingOn Saturday, Nottinghamshire Police said the man had not survived, adding that his family has been informed and were being supported by specialist officers.He had not been seen since Friday, prompting a large-scale search operation involving fire, ambulance, air ambulance, coastguard personnel and other search teams.Temperatures have since dropped towards the average for the time of year following the heatwave.Forecasters said the first day of June would feel 'more like spring or autumn', with thunderstorms and cooler temperatures expected.Tuesday was the hottest May day on record for both England and Wales, with 35.1C measured at Kew Gardens and 32.9C at Cardiff Bute Park.Met Office meteorologist Rebecca Mitchell said the heatwave was 'over' with 'big change on the way', including cooler temperatures, rain, possible thunderstorms and strengthening winds.