Building new homes in people's gardens posed a "significant" flood risk, the author of a government report into last summer's floods said.

Sir Michael Pitt, chairman of the independent inquiry, told BBC Radio Five Live that the "garden grabbing" surge by property developers had increased the risk of further flooding.

He told the broadcaster: "If it was just one house and one garden, this would not be an issue.

“It's the cumulative effect over time of many, many properties."

In his interim study released last month Sir Michael, Chairman of the South West Strategic Health Authority, called for flood planning to be elevated to the status of combating terrorist attacks or a flu pandemic.

His report made 15 urgent recommendations and 72 other proposals to prepare Britain to cope better with similar natural disasters.

It called for better weather forecasting, local authorities to become more involved in flood-risk management, emergency services to be better prepared and for buildings constructed in flood-risk areas to be flood resilient.

It also urged the Department for Environment, Food and Rural Affairs (Defra) to develop a national flood emergency framework.

The severe flooding in June and July followed the wettest May to June period since records began in 1766, and left 48,000 homes and 7,000 businesses in south-west England, the Midlands, Yorkshire and Humberside deluged with water.

Around 350,000 residents in Gloucester, Cheltenham and Tewkesbury lost their water supply for up to 17 days when a treatment works flooded.

And the disaster forced the closure of major roads such as the M1, M4 and M50, many railway lines and stations and generated insurance claims totalling GBP3 billion.