The death of a man who drowned as he rescued two children from the sea was one of a number of water-related tragedies as temperatures soared this weekend.
Most of the British Isles was bathed in scorching temperatures which reached 27C (80.6F) in places today.
But forecasters are predicting a gradual cooling during the week to come - culminating in a substantially cooler Jubilee bank holiday weekend.
The 25-year-old who drowned off West Wittering beach, near Chichester, West Sussex, had gone to the assistance of two youngsters who were playing in a rubber ring, Sussex Police said.
The news came as a man who died after getting into difficulty near a waterfall in a city park was named by police.
Nicholas Smith, 23, was pulled from the water in Linn Park near Simshill on the southside of Glasgow, and died later in hospital.
In a further incident, a 22-year-old man died after getting into difficulty while swimming with friends at a disused quarry at Ballykelly, near Monasterevin, Co Kildare.
His body was recovered by the Garda Sub Aqua Unit yesterday evening.
Yesterday's tragedies followed the death of a 15-year-old boy who drowned when he jumped from a bridge into the River Thames in Oxford on Friday night.
The body of the teenager, named locally as Hussain Mohammed, was not recovered for two hours after he was seen plunging into the water.
His death prompted warnings about the dangers of cooling off in rivers.
The sunny weather brought thousands of people out to see the Olympic torch relay today as it passed through south and west Wales.
Haverfordwest BBC Radio Wales DJ Owen Money, broadcasting from the town, warned that people were fainting in the heat.
“If you're coming, get some suntan lotion and water because people are fainting,” he urged anyone planning to join the throng.
The highest temperatures today were recorded in the south-east and the west of England as well as the north-west of Scotland.
By mid-afternoon today, Wisley in Surrey, had the highest temperature at 27.4C (81.3F). Another hot-spot was Porthmadog, in north Wales, which reached 26.9C (80.4F).
Yesterday's top spot, Kinlochewe in the Highlands, dipped from the 27.9C (82.2F) reached on Saturday to 25.8C (78.4F) today.
Forecaster Sally Webb of MeteoGroup, the weather division of the Press Association, said tomorrow will be another sunny day across most of the UK but temperatures will be slightly cooler.
She said this cooling trend will accelerate through the week.
“For most areas, tomorrow is going to another sunny day,” she said.
“But while it's still going to be warm, we're going to be looking at something like 26C or 27C in London and 24C to 25C elsewhere.
“So it will be a little bit cooler.”
Ms Webb said there was chance of thundery showers in some areas of central England but the area which will see the biggest difference will be north-east Scotland, which could be a lot cooler.
She said that by Tuesday a lot of the country would be cooler, especially in the north of England and Scotland.
And by Thursday, top temperatures are likely to be down to 17C or 18C and a similar level is likely to be maintained into the Jubilee bank holiday weekend.
Average maximum temperatures for England in May are 14C to 17C (57.2F to 62.6F), while Scotland would normally be between 13C and 15C (55.4F to 59F). Last week was the driest since the end of March, according to the Environment Agency.