The London Weather Centre reported that Jersey had the highest UK reading, with 33C (91.4F) - 0.1C higher than Gravesend, Kent, on June 7, the previous highest reading.
The warmest place on the mainland was Cranwell, Lincs, with 32.6C, and there were many readings of 32C (90F).
Sizzling England was one of the world's hot spots - warmer than Bermuda's 81F, Corfu's 82F, and 77F at Nice in the south of France.
The highest July temperature ever recorded in Britain was 36C (97F) in 1911.
By tonight cooler weather had begun to arrive from Scotland and the Continent, likely to lead to thunderstorms in the next day or so and an end to the hot spell. Next week temperatures are expected to reach the mid-80s at the highest.
There has already been heavy rain in south-west Scotland and the Western Isles, where temperatures only 15C (59F). Northern Ireland had light rain.
The hot weather prompted safety warnings about cooling off in lakes, rivers and reservoirs.
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