The record for the hottest day ever in Britain was broken on Sunday as temperatures soared to 38.1C (100.6F) in Gravesend, Kent.
People used London's fountains to cool down
The record was initially topped earlier in the day when Heathrow airport registered 37.9C (100.2F), meaning the hottest day since records began about 130 years ago in 1875.
The previous record was 37.1C (98.8F), recorded at Cheltenham in 1990.
However the heat has brought with it violent thunder storms, heavy rain and lightning across northern England and the Midlands.
More than 20 people were injured after being struck by lightning.
Fourteen were hurt when lightning struck a football match in a leisure centre in Birmingham on Sunday afternoon.
One woman was directly hit and had a heart attack, while others were treated for burns, eye injuries and shock.
In Lancashire, two Brownies were slightly injured when lightning struck between them at a camp near Blackburn.
'No spare sand'
Another six people were injured when lightning struck at an agriculture show in Corley, Warwickshire.
But elsewhere Britons have been soaking up the sunshine.
Brighton beach was crowded and chaotic
Roads to the south and west coasts were jammed on Sunday as motorists headed to and from the seaside.
Resorts including Clacton-on-Sea in Essex and Tenby in Pembrokeshire said there were no spare beds at all in hotels and B&Bs.
At Bournemouth in Dorset, the coastline was crammed to capacity with about 100,000 sun lovers and "no spare sand".
Brighton beaches were crowded and chaotic, with the sea front office saying: "There have been lots of lost children, pier jumpers, drunks and
other shenanigans which we are dealing with."
Topping 99F and then 100F means a bad day for the bookies, with William Hill alone having to pay out over £250,000.
Spokesman Graham Sharp said "plenty" of people would have won bets at up to 25-1 that the temperature of 100F would be beaten.
The Met Office's chief weather forecaster Nigel Reed explained why the weekend has been so hot.
A cold front out to the west of the UK has been "pulling in exceptionally warm air that's been over northern France the last couple of days," he said.
"The longer a hot spell lasts the higher the temperature gets each day, typically about a degree each day."
He said the recent hot weather was "consistent" with global warming, although it was impossible to prove an exact link.
Summers this hot or hotter may even become fairly "routine" within 50 or 70 years, he said.
Not everybody in the UK enjoyed sunshine
"In the years to come, as the earth's atmosphere does heat up through global warming, we would expect to see these hot weather events happening with greater frequency," he said.
The hot weather is expected to continue in the south of England into next week although it will be cooler and fresher by mid-week.
Delays on the railways continue due to speed restrictions imposed by Network Rail at noon each day while temperatures remain above 30C.
There are currently no water shortages.