Torrential rain, a creaking sewer system and a lack of drainage have left Islington at serious risk of flash flooding, it is claimed.

Despite being one of the highest places in London, which means the borough is unlikely to face the river-based flood chaos affecting many parts of the Thames Valley, over developing and a failure to replace Sustainable Urban Drainage Systems (SUDS) leave Islington facing real danger of rising water levels.

And Caroline Russell, from Islington’s Green Party, will demand assurances from the town hall at a full meeting of Islington Council on Thursday.

Her question for Cllr James Murray, Islington Council’s executive member for housing and development, is: “In view of the rising threat of urban flooding from heavier rainfall patterns, what examples are there of SUDS being incorporated in new developments, as made a council commitment by Katie Dawson in 2009?”

Cllr Dawson was a Green member of the council until 2010 who extracted a promise that plans for all new buildings would replace any drainage ground – like grass – swallowed up in the development.

Ms Russell added: “There is a real danger of our Victorian drainage system being overwhelmed.

“The more you build and cover up green areas, the more surface run-off the system has to deal with. We may be miles away form the river but there is a serious danger of flash flooding with this extreme weather and torrential rain.

“We also have a duty in Islington to protect those places near the river. Rather that just letting our water flow into the drains and head into the Thames, we need places where it can dissipate and evaporate slowly.

“It’s an old system and dense building puts it under too much pressure.”

Cllr Murray said: “We have a very strong planning policy to stop developments causing flooding. No development is allowed to increase run off, and major ones actually have to decrease it.”