A row centred on a bid to build houses at a creative and cultural haven in Cornwall has escalated, with opponents saying use of a “technical loophole” would be an abuse of the planning process.

Evolving Places Ltd has applied to Cornwall Council for a certificate of lawfulness to allow permission granted almost 30 years ago to stand to convert a “redundant” barracks at Maker Heights, near Torpoint, into six homes.

However, those against the proposal – including Rame Conservation Trust (RCT) – say that circumstances have completely changed since the 1997 approval and site is far from redundant, with the barrack block being listed as a protected building since then.

More than 65 people who have commented against the application on the council’s planning portal argue that over the past 25 years Maker Heights has become one of the most significant creative and cultural assets in South East Cornwall.

It hosts live music venues, artists’ studios, youth music sessions, a thriving cocktail bar and numerous small businesses run by local people. It draws thousands of visitors from across the country and provides livelihoods, community connection and “creative purpose to a great many people”.

Former military land which played an important role in the defence of Plymouth from the late 18th century, the site contains five scheduled monuments, 17 Grade II* listed buildings and is situated in the protected Rame Head area of the Cornwall National Landscape (formerly designated area of outstanding natural beauty).

Local anger over Evolving Places’ plans for the site was first reported last year.

RCT, a registered charity, was formed in 1997 to protect and promote the heritage assets at Maker Heights for public benefit. Other parts of the site, including a number of outbuildings and some adjacent land, are owned and managed by Evolving Places, which also runs the Seaforts Glamping site at Maker Heights.

Evolving Places previously submitted a part-retrospective planning application with Cornwall Council to change one of the buildings, the Straw Store, into residential use, which it said would help with the financial upkeep of the site.

However, local residents, other users of the site and the RCT were not happy, believing that Maker Heights is wholly unsuitable for residential properties.

The application was refused by the council’s planning department last November.

Parker Dann chartered town planners have submitted the new application on behalf of the company to establish that the planning permission granted in 1997 for the conversion of the barracks to six residential units and the alteration of access to the highway “has lawfully commenced and therefore remains extant”.

A planning statement said: “The applicant respectfully submits that the evidential burden has been met on the balance of probability and that a certificate of lawfulness for existing development should be granted.”

Tonny Steenhagen, who lives near Maker Heights, said: “Evolving Places do not own the barrack block as this is ‘owned’ by the Rame Conservation Trust. In other words, permission granted in 1997 to turn the site into six domestic units is literally, practically and materially impossible. On this ground alone this sought certificate should be turned down.”

Another resident, Charlotte Turner, added: “This application attempts to rely on a permission granted in 1997 that was never meaningfully implemented. The site has changed fundamentally over the last 30 years.

“The characterisation of Maker Heights as ‘redundant barracks’ – which underpinned that original consent – bears no resemblance to what exists today. To permit residential use on the basis of a technical loophole rooted in that outdated description would be an abuse of the planning process, not a proper exercise of it.”

“The community has expressed its view on this matter consistently and clearly over many years. Residential development at Maker Heights cannot, should not and will not ever be appropriate for this site.”

Writing on the planning portal, Rory Mundell Perkins added: “The barrack block is now a Grade II* listed building and the site as a whole is of great historical significance.

“This application appears to be trying to exploit a potential loophole in the planning process rather than acquire up-to-date relevant planning permission.”

Chris Moloney said: “To destroy it [Maker Heights] for the benefit of a few developers and a handful of new residents would be nothing short of vandalism.”

Ursula Stevenson has also spoken out on behalf of the RCT. She said: “The proposed development cannot form a residential enclave of six dwellings, nor two dwellings and residential outdoor centre, as originally intended as the barrack block is in our ownership.

“There have been changes to status of heritage. The listed buildings that form the application were upgraded to Grade II* in July 1998 and proposals would require demolition, alternation and other impacts on the buildings. The building complex at Maker Heights is considered to be one of the finest collections of Napoleonic buildings in the country.”

Evolving Places have been contacted for a comment in response to concerns on the Rame Peninsula.