Residents have warned that plans to build scores of affordable homes on former school playing fields would see the irreversible loss of the area’s last ‘environmental green lung’.

A public inquiry has opened into Sovereign Network Group’s (SNG) proposed 84-home scheme in Bitterne.

The developer is seeking to overturn the refusal decision of Southampton City Council’s planning and rights of way panel for the former St Mary’s Independent School site.

The application was turned down by councillors due to the loss of the open space and playing, the design of the scheme and the impact on residential amenity in Monastery Road from increased traffic.

Speaking on the first day of the inquiry at the Civic Centre on Tuesday, Kevin Leckey, spokesperson for the St Mary’s Local Residents’ Opposition Group, said 187 objections were submitted against the plans.

He told the inquiry that brown and grey belt sites in Southampton had “substantial” housing development opportunities, but they were “lying in waiting, idle, redundant and unactioned”.

Mr Leckey referenced nearby Townhill Park, as well as designate sites of the Bargate, ToysRUs and Debenhams in the city centre.

“We believe this is the area’s one remaining ‘environmental green lung’,” Mr Leckey said.

“The green corridor that safeguards our air quality for now and the future.”

He added: “As local residents we understand the enormity of such a development and consider that to be at the absolute expense of public opinion, open space recreation and the environment.”

The opposition group spokesperson said the proposed site access at the top of Monastery Road would be a “shocking infringement” on the adjacent family home.

He also expressed concerns over drainage and flooding, traffic and capacity in local services.

SNG’s proposals include a contribution of more than £600,000 to make improvements at Riverside Park.

Mr Leckey said: “We respectfully submit that no matter what that contribution is, it will be provided for Riverside Park and that affords no meaningful compensation for the loss of St Mary’s sports field.

“It is funding for an area separate and distant to this lost sports space. We believe it is not replacing like for like.”

The development plans consist of eight one-bed flats, 24 two-bed flats, 27 two-bed houses, 22 three-bed houses and three four-bed houses.

SNG has said it can use its strategic partnership grant from Homes England to deliver the scheme as 42 social rented and 42 shared ownership homes.

Graham Linecar, of Southampton Commons and Parks Protection Society, said he was speaking in objection as the proposal challenged a matter of principle.

He said the society fought hard to secure the core strategy policy that the council will retain the quantity and improve the quality and accessibility of open space.

“The development plan designates this site as open space,” Mr Linecar said.

“It is irrelevant in applying this policy whether there is public access or it is private playing fields or other green space.

“The purpose of the policy is to protect green space.”

He added: “The appellant is arguing the need for housing outweighs the policy protection of green space and that’s where SCAPPS fundamentally disagrees.”

In opening the appellant’s case, Christopher Young KC said the scheme was “generous and thoughtful”, with public benefits that went “significantly beyond” would what normally be achieved through policy in terms of affordable housing, open space, landscaping, biodiversity net gain and mitigation.

He said these benefits “demonstrably” outweighed the “very limited harms” that had been identified.

“Proposals for the delivery of 100 per cent affordable housing are extremely rare and absolutely vital now in Southampton where it is common ground that there is an acute affordable housing need,” Mr Young KC said.

Rebecca Sage, on behalf of the council, said the proposal would cause “very substantial harm” through the loss of the open space to the character and appearance of the area, and to the amenity of Monastery Road residents.

“The appellant’s case appears to be that, in the event there is a conflict with the development plan, which the council says there is, the need for new and affordable housing in the city should justify the grant of permission, come what may,” Ms Sage said.

“The council does not accept that approach.”

The site was part of the St Mary’s Independent School grounds up to its closure in 2020.

It is currently fenced off with a locked gate.

Government-appointed planning inspector John Longmuir is expected to hear evidence at the inquiry until the latter stage of next week.

He will then consider all the material presented to him before reaching a decision.