Police are searching for a 15-year-old boy who has not been seen since he went into a lake in Lincoln.
Emergency services were called to Swanholme Lakes at 2.30pm on Sunday after reports that the boy had got into trouble in the water.
Lincolnshire Police said in a statement later in the afternoon: ‘Despite the very best efforts of people at the lake and the emergency services who arrived on scene, the boy has not yet been located.
‘We continue to search the lake and our underwater search team will be assisting with this.
‘We have informed the family of the boy and our thoughts are with them at this incredibly difficult time.’
The force warned against speculation about the incident and said information that the boy had been found was wrong.
Swanholme Lakes is a local nature reserve and a nationally recognised Site of Special Scientific Interest (SSSI).
It is provisionally the UK’s hottest May day in 79 years as temperatures soared to 32C in Heathrow.
Swanholme Lakes is a nature reserve about three miles from Lincoln city centre
On Thursday, it was announced that temperatures were set to soar across much of the UK as high pressure brings increasingly settled, dry and sunny conditions, with forecasters warning that record-breaking heat is possible over the Bank Holiday weekend.
The Met Office said temperatures will climb steadily through the weekend, reaching around 30C on Saturday and 32C on Sunday in southern areas, before potentially peaking at 33C on Monday across southern England and the Midlands.
Forecasters say the current UK May and spring temperature record of 32.8C could be broken.
Heatwave conditions, defined as three consecutive days above local temperature thresholds, are expected to develop from Sunday, initially in south-east England before spreading more widely.
The Met Office said the heat is being driven primarily by a strengthening area of high pressure over the UK, which warms descending air through a process known as adiabatic compression, rather than by a direct influx of hot air from southern Europe.
Health and safety agencies are urging the public to take precautions as people head outdoors and to the coast over the Bank Holiday.
Amber heat-health alerts have been issued for parts of England, with warnings that vulnerable people could face increased health risks.
Scientists also say climate change is increasing the likelihood of record-breaking May temperatures, with research suggesting such extremes are now around three times more likely than in a climate unaffected by greenhouse gas emissions.
In Lincoln, the temperature earlier was about 25C, according to the Met Office.
