Test Valley Borough Council (TVBC) has begun the process of unblocking a backlog of housing after investing in a new scheme that allows construction while protecting the environment.

The council has bought credits at Roke Manor Farm, where land which was previously used for farming will now be held as an “environmental asset” to mitigate nitrate pollution in the Solent. In February, rules surrounding this pollution were estimated to be holding up the construction of around 750 houses.

Portfolio holder for planning, Councillor Nick Adams-King, said: “We’re really grateful for the joined up working of Roke Manor Ltd and Natural England in seeing this come to life. The past two years have been difficult in ensuring our planning process balances out any increase in nitrate levels in the Solent, which is something we need to achieve in order to protect the environment in delivering new homes to meeting our housing needs.

At present, all accommodation and tourism attractions across much of Hampshire must be nitrate neutral. Nitrates are generally generated by new housing, mostly in wastewater, amd have to be mitigated by other actions, such as taking agricultural land out of use, or introducing plants and animals that use nitrogen to grow.

This requirement is due to a 2018 EU court ruling, which led Natural England to subsequently advise planners in areas with rivers that drain into the Solent that their developments should not add excess nitrates. This is designed to protect the Solent by preventing eutrophication, where nitrogen allows algae to grow rapidly and starve marine life of oxygen and light.

At a February meeting of TVBC’s Overview and Scrutiny Committee, the council revealed it had had 93 planning applications which it would approve but could not due to nitrate neutrality rules. This is a total of 502 houses, with an estimate that up to 50 per cent more may be prepared but not yet submitted for approval. Cllr Adams-King has previously described the rules as "one of the greatest challenges" faced by Test Valley.

TVBC has been preparing an offsetting scheme to counter this, with land that produces excess nitrates, such as farmland, being taken out of food production to counter the excess nitrates produced by new housing.

It will charge developers £3,000 per kilo of nitrogen that cannot be offset on the development site, as well as a £100 administration fee. This money will be used to secure land for at least 80 years to offset the development, with the possibility of converting agricultural land to woodland or wetland to do so and opening it to the public in some instances.

In the case of Roke Manor Farm, the credits purchased by the council will be used to offset smaller schemes within Test Valley, with larger schemes able to purchase credits directly from Roke Manor Ltd.

Ollie Mitchell, from Roke Manor Ltd, said: “We are delighted to have worked with TVBC and Natural England to design and secure land at Roke Manor Farm as strategic nitrogen mitigation land, and look forward to working with the council and applicants alike to support residential development in the Test Valley and mitigate nitrogen impacts on the important habitats of the Solent.”

The scheme also has the backing of Natural England, the body responsible for the nation’s environment, with Allison Potts saying: “We support the work TVBC has done to secure the credits from the Roke Manor site to protect the Solent from increases in nitrates. We are excited to see it develop into a wonderful place for wildlife and a great environmental asset for the borough and its residents.”