Flash flooding earlier this year was not caused by a build-up of debris despite only half of gullies in the area being cleaned ahead of the incident, according to officials.

Several residents have yet to return to their homes, in Chatham, due to the damage caused by the heavy rainfall in May, with the Victory Care Home in Nelson Terrace being the worst-affected property.

A Medway Council report discussed last week (August 16) identifies only 20 of 45 gullies in the area (Capstone Road, Nelson Terrace, Queens Road and Beacon Road) were cleaned ahead of the flood.

Vehicles parked on the roadside are blamed for the low rates of inspection, but Cllr Tristan Osborne (Lab) pointed out a number were in double yellow line areas. This is now being investigated.

However, both council and Southern Water officials do not believe this led to the flooding, instead being a result of “sewer overloading and overland surface water flow”.

Priscilla Haselhurst, the authority’s flood drainage officer, said: “Highways gully systems take a very small amount of water, and the Southern Water system will take a little bit more water.

“It is designed to take rainfall at the site, and doesn’t take into account overland flow, and that’s something that’s always been the case through legislation.

"Once in a lifetime event" - Southern Water describing the flooding earlier this year

“It is changing, but the traditional system is designed to take water from there and then.

“Essentially, you’ve got a huge amount of water which you’re trying to fit into a very small area.”

Southern Water admitted that the likelihood of the drainage systems in the area being upgraded were “low”, describing the flash flooding as a “once-in-a-generation” event.

Jean-Paul Collet from the company added: “Our finances are finite as well, and we do have to direct those to areas where flooding is prevalent and is occurring more often, and has a larger history of that.

“That doesn’t mean investment isn’t going to happen – this event is now logged on record, and it does fall into the system that drives our investment strategy.”

Southern Water has vowed to revisit the area to carry out further tests, as well as repair lining on part of the sewer in the next “four-to-six weeks”.

A letter is also going to be sent to affected residents, some of which will not be able to return to their homes until this December.

Cllr Tristan Osborne (Lab), ward councillor for Luton, added: “A lot of residents would feel more secure, and that is important.”