More than 10,000 homes in Norfolk could have planning permission delayed due to measures introduced to keep the county’s waterways clean, analysis has found.

The hold-up has been caused by new restrictions affecting the county’s planning systems, following the advice of government body Natural England.

Norfolk’s councils were informed that they must not grant planning permission for any schemes involving 'overnight accommodation' until they can prove developments would not lead to phosphates and other nutrients flowing into the River Wensum and the Broads.

The catchment area affected by the new regulations covers a large chunk of the county, encompassing all of Norwich and most of Broadland, south Norfolk and north Norfolk, along with smaller parts of Breckland, Great Yarmouth borough and west Norfolk.

Natural England and the Department for Environment, Food and Rural Affairs (Defra) say councils need to make assessments against which developers can prove their schemes are nutrient neutral - by providing mitigation if necessary.

Several senior councillors have raised concerns about the way in which the new requirements were “dropped” on them without the offer of transitional arrangements.

Sue Lawn, Broadland District Council’s Conservative portfolio holder for planning, said: “There should have been a lot more communication before they decided to drop this on us, and there should be a lot more communication about what they expect [in terms of mitigation].

“They need to give us a lot more guidance.”

Ms Lawn said she was concerned about small developers in particular.

"The big developers can get on and do what they have to do on other sites [outside the affected area], but for the small developers it’s just unfair," she added.

She was joined by North Norfolk District Council’s Liberal Democrat leader, Tim Adams, who said: “After this emerged, I had someone ring me to say ‘this is an April Fools Day joke, isn’t it?’.

“People who had applications about to be approved are angry and disheartened. They’ve all been so good about understanding our position.

"We're also in the middle of an inflationary crisis and I’m concerned about the impact on local builders and builders’ merchants - it's a recipe for problems."

While both Ms Lawn and Mr Adams agreed that more work was needed to keep the county’s waterways free from pollution, they said the new measures had left their councils with no time to put new arrangements in place to approve homes.

South Norfolk Council’s Conservative leader, John Fuller, held a meeting with lawyers on Wednesday (April 13) in order to better understand the options available to the affected councils.

Mr Fuller, who serves as chair of a board coordinating planning issues across the county’s authorities, said the discussion had left him “confident that an acceptable way forward for the determination of planning applications is possible in weeks, not months”.

On Thursday (April 14), Mr Fuller will meet with colleagues from other Norfolk councils to discuss whether a "common approach" can be found to respond to the new requirements.

“It’s a complicated situation and I need to brief colleagues on some of the fine detail,” he said.

An analysis of the number of homes making their way through the planning system within the area affected by the new measures shows that at least 10,000 will not currently be able to receive formal sign-off to be built.

Some of that number, such as the proposed 1,100 homes at Anglia Square in Norwich, are still some months from being formally considered for permission.

However, uncertainty remains over how long it will be before the authorities are again able to grant such permissions.

In North Walsham alone, consultations have taken place on some 2,150 homes across two sites, but neither development can be given formal approval until NNDC has worked out how to satisfy Natural England’s requirements.

Several projects included in the analysis already have permission in principle, such as a plan for 950 new homes in Fakenham.

The northern edge of the Wensum river catchment cuts directly across that site, making about a quarter of the land currently unusable for homes.

The layout of the development is still to be agreed, so it is not known how many of the 950 houses cannot, for the time being, be built.

Other major housing schemes are outside the catchment areas, such as the planned 4,000 homes in Attleborough.

A Defra spokesman confirmed that the new measures were permanent and would not be reversed.

In a blogpost, Defra's director of sustainable development Melanie Hughes said that advice, guidance and tools to respond to the new requirements had been issued to councils.

She said: "We recognise that nutrient neutrality won’t be easy to adopt in many cases.

"But we would like to assure our stakeholders that Natural England, working alongside our partners, will support planning authorities and developers to implement it effectively so that they can build sustainable new homes and contribute to healthy rivers, lakes and estuaries nearby."