Emergency services have launched a search operation for a 15-year-old boy who was last seen swimming in a lake near Southampton.
The teenager was reported missing after being last seen swimming at Testwood Lakes, near Totton, Southampton.
The alarm was raised at 1.35pm on Wednesday.
Hampshire Constabulary confirmed a multi-agency effort is underway to locate him.
A spokesman said: “A multi-agency operation is under way following a report that a 15-year-old boy is missing after he was last seen swimming at Testwood Lakes near Totton.
“This was reported to police at 1.35pm on Wednesday 24 June and the area is currently off limits while our search operation is ongoing. Please avoid the area at this time.”
Police marine units are assisting in the search, alongside colleagues from the National Police Air Service (NPAS), South Central Ambulance Service, and Hampshire & Isle of Wight Fire Service.
It comes as Wednesday saw the hottest June date on record.
Provisional temperatures of 36C were recorded at both Wisley, Surrey, and Gosport in Hampshire, the Met Office said.
It follows recordings of 35.8C and 35.7C in Wiggonholt, West Sussex and Charlwood, Surrey respectively.
This new peak surpasses the previous high of 35.6C, which was jointly held by 1976 and 1957.
The Met Office warned that these figures were expected to climb further, with more records potentially falling in the coming days.
A rare red warning for extreme heat in place for Wednesday and Thursday was extended down to the south coast of England, including Brighton, Bognor Regis, Portsmouth, Southampton, Bournemouth and Dorchester, the Met Office said.
Red heat health alerts have also been issued by the UK Health Security Agency (UKHSA) for the East of England, East Midlands, London, the South East, the South West and the West Midlands, and amber heat health alerts for the North East, North West, and Yorkshire and The Humber.
The Met Office has also issued an amber warning for heat on Friday covering much of England, while a yellow warning for thunderstorms is in place for the South West on Thursday evening.
And with the extreme heat set to linger in some parts of the country into the weekend, the Met Office has issued an amber warning for extreme heat covering parts of east and south-east England on Saturday.
The forecaster added it may need to issue further updates on the extreme weather as more details on the conditions become clear.
Grahame Madge, Met Office spokesman, said: “We have issued another amber warning for eastern and central England for Friday.
“As the forecast continues to evolve we may need to issue further updates once more detail becomes clear.”
