Rescue teams are scouring through a country park after a teenage boy went missing in the water on the hottest day of the year.
Emergency services scrambled to Rother Valley Park in Rotherham, Yorkshire, shortly before 7pm on Monday as temperatures soared beyond 30C.
A teenage boy had earlier been seen entering one of the scenic park's four lakes, but had not been spotted getting out.
The missing person is yet to have been found, despite crews and a helicopter working through the night in a bid to find him.
Rother Valley Park stretches across three sq km and is located near Rotherham's border with Sheffield and Derbyshire.
A spokesperson for South Yorkshire Police said: 'We were called to Rother Valley Country Park at 6.50pm following reports that a teenage boy had entered the water but had not been seen getting out.
'Officers are in attendance alongside emergency crews from South Yorkshire Fire and Rescue Service and the Yorkshire Ambulance Service and efforts are ongoing to try and find him.
'The search is continuing into the night and updates will be provided as soon as possible.'
Emergency services scrambled to Rother Valley Park (pictured) in Rotherham, Yorkshire, shortly before 7pm on Monday amid reports that a boy had gone missing in the water
It came on a day where temperatures soared beyond 30C across the United Kingdom (One of Rother Valley Park's four lakes is pictured)
The boy's disappearance comes on a day when nine British counties saw record-breaking temperatures amid a heatwave described as 'historic'.
The 34.8C recorded in Kew Gardens, south-west London, made it the hottest May Day on record - surpassing the previous high set 82 years ago.
In Rotherham, temperatures reached peaks of around 32C on Monday afternoon.
Crews trying to find the missing teenager at Rother Valley Park tonight will have to do so in heats of more than 20C.
Authorities had warned Britons about the dangers of swimming in reservoirs and lakes prior to this weekend's heatwave.
However tragedy struck in Lincolnshire when a 15-year-old died in a lake near his family home on Sunday as temperatures touched 27C.
A huge search operation was mounted to find Declan Sawyer after he was reported to have got into difficulty while swimming in Swanholme Lakes.
Lincolnshire Police later announced that the teenager's body had been recovered from the water on Sunday evening.
Declan's aunt Lindsay Sawyer paid tribute to him with a moving tribute on Facebook reading: 'Words cannot describe how utterly heartbroken we are.. how life can change so fast and in such a tragic way…… we loved you like you was our own , looking at all the amazing memories you shared with us….
'RIP Declan forever in our hearts… x.'
Nine British counties saw record-breaking temperatures on Monday amid a heatwave described as 'historic'(Beachgoers are pictured in Weymouth)
Elsewhere, a man died in Hastings on Sunday while spending his afternoon on a packed beach.
Emergency services including an air ambulance scrambled to the scene after a 'medical incident'.
The man tragically passed away at the scene, on the beach near Warrior Square in St Leonards.
A spokesperson for Sussex Police said: 'Emergency services responded to a medical incident on the beach near Warrior Square, St Leonards, following concerns for a man's welfare.
'Officers assisted with the emergency response after the incident was reported at 11am on 24 May. Sadly, despite the best efforts of paramedics, the man was declared deceased at the scene.
'His next of kin have been informed and our thoughts are with them at this difficult time. There were no suspicious circumstances and a report will be prepared for HM Coroner.'