A 17-year-old girl died when the vehicle she was in plunged into a swollen river as torrential rain flooded homes and caused transport chaos in Britain.

The girl was one of three passengers in a 4-wheel-drive vehicle which careered into the river in the flood-hit Powys region of Wales, a police spokesman said.

The two other passengers, a man and a woman, were airlifted to safety but were suffering from hypothermia, he said.

The Taff river in south Wales burst its banks and the government's Environment Agency published 40 other flood warnings on rivers in England and Wales.

Overflowing rivers and storm drains flooded houses and stranded motorists in Wales and southwest England.

Forecasters said there was more heavy rain to come and said there could be more flooding as the storms moved north.

The South Wales Fire and Rescue Service said it had received more than 350 flooding calls in a six-hour period, including calls to help people trapped in their cars by rising water.

Roads were impassable in parts of Wales while police in Gloucestershire, southwest England, warned motorists to travel only if necessary because some roads were under water.

Rail company Arriva Trains Wales also advised passengers not to travel.

Phil Rothwell, head of flood risk at the Environment Agency, urged people in flood-prone areas to watch weather forecasts.

"Rivers are rising very rapidly and bursting their banks, also the drainage system that takes the water away from our urban areas is also failing," he told BBC television.

Over the next 24 hours he said the heavy rain was forecast to move northeast, through central England and into Yorkshire and northeastern England.