A woman was killed by a falling tree branch in London's Kew Gardens during rain and gusts of wind close to 30mph.
The woman, believed to be aged about 30, was pronounced dead at the scene on Sunday afternoon on a day when strong winds and rain began to lash southern parts of the country.
Wind speeds in the area around the Royal Botanical Gardens reached a peak of 30mph on Sunday and were likely to be close to that at the time of the woman's death, Tom Tobler, forecaster with MeteoGroup, said.
Her death came as communities around the country braced themselves for wind speeds of up to 70mph and rainfall of up to 60mm in some regions over the next 24 hours. The Environment Agency has issued has 56 flood alerts - 31 in the south-west, 19 in the north-east and six in the Midlands.
Mr Tobler said north-east Scotland could be hit with the strongest winds, with gales of up to 70mph possible.
He said northern areas of England and parts of southern Scotland could see 60mm of rain fall in the next 24 hours - three quarters of a whole month's average rainfall (80mm) for September in England and Wales.
It is a stark change from earlier in the month, when parts of Britain basked in warm temperatures in the mid-20s, a welcome break from the rain and wind which dogged much of July and August.
The Environment Agency has warned people to be prepared for significant disruption. iirector of operations, David Jordan, said: "We are expecting flooding across the country from this evening (Sunday) and in to Monday and Tuesday.
"We strongly urge people to sign up to flood warnings, keep a close eye on local weather forecasts and be prepared for the possibility of flooding. We also ask that people stay safe, by staying away from swollen rivers and not attempting to drive through floodwater."
The woman's death at Kew is not being treated as suspicious and a police spokesman could not confirm whether the matter would be referred to the Health and Safety Executive (HSE).