Britain will review its flood defences after a powerful storm caused severe flooding, swamping hundreds of homes and leaving two dead, Prime Minister David Cameron says.

The Conservative leader on Monday visited Carlisle, a city in the hard-hit Cumbria region of England, where he viewed a flooded home and met soldiers who helped evacuate the area.

“It’s an absolutely horrific thing to happen and for some of these people it’s not the first time it’s happened,” Cameron said, adding that the Environment Agency would study how to improve flood barriers.

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“We will ask all those questions because people want to live free from the fear of being flooded. We need to make sure they get all the support they need.”

Cumbria police declared a “major incident” after the region was lashed by Storm Desmond, and weather warnings were issued for the rest of the week.

A body was discovered in a search of Cumbria’s River Kent after reports that an elderly man had fallen into the water.

And there was also a death reported in London, after a man was blown into the path of a bus.

More than 350 military personnel were deployed in Carlisle to help evacuate homes as the water reached waist height in places.

The incident raised questions over why barriers built following serious flooding in Cumbria in 2005 failed to contain the weekend’s heavy rainfall, in which 2000 buildings were flooded.

Following criticism, the Environment Agency said STG45 million ($A93 million) had been spent on the defences in the last decade, and described the rainfall as “beyond the forecasts and beyond the models”.

The storm left tens of thousands without power, disrupted water supplies and forced the closure of a number of schools.