Flooding fears have prompted calls for controversial development plans to be reviewed.

Campaigners are trying to stop St William Homes’ plans for 66 flats at the former gasworks site in Wharf Lane, Rickmansworth.

Paul Sansom-Timms, owner of Croxley Hall Fisheries, fears water could flood the development after watching it come "within a centimetre" of breaching The Chess Wall, which is the last line of flood defence, last February.

Parts of Rickmansworth were submerged for days last February after the River Colne burst its banks following record rainfall in January.

A letter sent by the Environment Agency to Three Rivers District Council in 2012, stated: "With climate change taken into account, the Chess Wall would be overtopped in a 1 in 100 year flood event and result is flooding of approximately 80 per cent of the site.

"The SFRA [Strategic Flood Risk Assessment] has identified that as part of any residential development proposals, the applicant would need to look at increasing the size of the Chess Wall."

Mr Sansom-Timms said: "The Chess Wall is supposed to stop Rickmansworth flooding. It was built 30 years ago and from the data they had at the time.

"We haven’t had rain for about ten days and water is still laying there because the water table is the same level as the lake. Rickmansworth High Street is lower than that by a couple of centimetres.

"When you see water pouring into your property, flooding your lakes out and you’re thinking about half a million pounds of fish stock, it becomes very real indeed. Flooding is an amazing thing when you see it and very frightening and very worrying.

"I worry for Rickmansworth because if we have a major flood worse than last year and it will only get worse, Rickmansworth will flood and it will go straight over the gates and the wall and flood the development site.

"I think it should be looked at in much more detail. The site has always been allocated for development. If the proposal had been for 20 houses with an upgraded flood protection, it would have been fine, but it is the fact they are trying to build so many flats without any upgraded flood defence which is the problem."

A representative for the Environment Agency told the Watford Observer The Chess Wall could not be raised because it would increase the risk of flooding elsewhere.

The statement read: "We explained that it would not be possible for them to compensate for this increase in off-site flood risk as part of their development proposals.

"The developer has now included flood mitigation measures as part of the development, including an area to store flood water, and property-level protection.

"We view the proposed measures as being acceptable to mitigate against the risks encountered at the Wharf Lane site during a 1 in 100 year flood event, allowing for climate change, with the current Chess Wall defence in place. It would also not increase flood risk off-site".