The storms began Monday and were expected to continue into Wednesday, The Independent reported.
In Manchester, a lightning strike at Manchester Piccadilly, the largest rail station in the region, delayed trains and frustrated commuters during Tuesday's morning rush hour, The Manchester Evening News reported. All service was suspended for some time, and trains were delayed for at least an hour, officials said.
The storms broke the longest heat wave in the country in years. In London, the high temperature Monday was 92.3 degrees, the highest recorded in the city in seven years, the Independent said.
A short time later, south London was battered by large hailstones.
Brendan Jones, a forecaster at MeteoGroup, said the prolonged heat wave increased the risk of flash flooding. He said the ground has baked hard, leaving rainfall with no place to go.