The Government’s environmental watchdog adds that investment in the building and maintaining of flood defences will need to almost double to £1bn a year by 2035, as climate change increases the risk of coastal erosion and flooding from rivers and the sea.

Around 5.2m properties are already at risk of flooding, with 2.4m threatened by rivers and the sea, and a further 2.8 million at risk from surface water flooding from overflowing drains.

The agency's Flooding In England report warns that thousands of health centres and doctors' surgeries, schools and miles of railways and roads are also at risk.

The highest number of properties at significant risk are in the South East of England, where 111,356 are threatened with flooding while Boston, Lincolnshire, has the greatest number of properties at high risk - 23,700 - of any local authority.

Without increasing funding for defences, the annual cost of damage to residential and commercial properties could rise from £2.5bn to £4bn, the agency warned as it released its long-term investment strategy for England.

The Environment Agency’s chairman Lord Chris Smith said:

"The latest UK climate change data shows that the risk of flooding and coastal erosion will continue to increase in future due to rising sea levels and more frequent and heavy storms, and there are important decisions for us all to take about how to manage these risks to protect people, communities, businesses and the economy in future.

"The Environment Agency has completed 90 flood defence schemes since summer 2007, providing increased protection to over 58,000 properties. Whilst continued investment in managing these risks is crucial, we cannot always prevent flooding so communities need to take responsibility for being prepared - for example by signing up to the Environment Agency’s free flood warning service."