A Grade-II listed bell tower at a former fire station went up in flames after being struck by lightning during the heatwave.
Twenty firefighters were called to the building in Wimbledon, south London when the storm hit last night.
Photos show flames rising and smoke billowing from the landmark - which dates back to 1890 - before cherry pickers were used to survey the damage.
The strike happened at around 6pm.
'It's not something you see every day'
Property manager Barry Daly, 32, witnessed the aftermath of the lightning strike while walking his dog at 8.30pm.
He said: "I was surprised to see the fire brigade and the blue flashing lights as I approached.
"The fire was out at that stage but people were saying it had been struck by lightning.
"It's a five minute walk from where I live so I pass by the clock often.
"It's not something you see every day."