Flash floods will become more common unless action is taken to defend Sutton's streets from extreme weather, councillors have been warned.

The drainage system at a Wallington flooding trouble spot where three drivers were rescued from submerged cars amid heavy rainfall is not designed to cope with intense downpours, a senior council officer said.

One of the drivers, Graham Price, was pictured swimming to safety in Manor Road after climbing out of the window of his Mercedes on June 7.

Storms wreaked havoc in south London as a tenth of the average year's rain fell in 75 minutes.

Roger Archer-Reeves, interim lead officer lead for highways and transport at Sutton Council, warned: “These rainfalls are extreme and are becoming more common due to factors like climate change.

“These sort of storms will start to get worse and we need to find ways to manage it."

Sutton Council said it cleaned the gullies under the road every three months after pictures of the dramatic scenes in Manor Road made international news and prompted calls for action to prevent further flooding.

The drainage system was last cleaned before the flooding on April 14.

But Mr Archer-Reeves, speaking at a scrutiny meeting on Wednesday last week, said: "The way the road is means sewage and rainwater collects below the bridge and it’s the intensity of the rainfall - it is extreme - that is the cause of the problem.

"The drainage systems can cope with it if it happens in a larger timeframe. It’s a system that was not designed to deal with the change of intensity of the rainfall."

The installation of a device to monitor levels in the drains and alert drivers about potential floods being considered by the council.

Mr Archer-Reeves said: "The embarrassment is that a driver can see the sign that the road is flooded. It’s a negative message, but there might be a place we can do this with your blessing.”

A monitor in the drainage system that could alert drivers the road floods.

Thirty-nine cases of flooding were reported in Sutton between on June 7 and June 23.