PLANS for redevelopment work at a long-forgotten Charles Rennie Mackintosh masterpiece in the centre of Helensburgh have been approved by Argyll and Bute Council.

Architects Bruce and Nicola Jamieson, owners of the Mackintosh Club, submitted the planning application to form a top floor and attic gallery and create a roof terrace at the property in Sinclair Street.

They are delighted that their proposals to safeguard the future of the category A listed building were approved.

The main recognisable features of the former Conservative Club will remain unchanged. The design of the new roof takes its inspiration from Mackintosh’s own modifications to the Glasgow School of Art, which was built in two phases.

In the case of the Mackintosh Club in Helensburgh, it is the rear roof that is being replaced so will not make any noticeable change to the main Sinclair Street elevation, nor be visible from Maitland Street. The new roof will feature a hidden rooftop terrace which the couple say will provide a completely unique experience for visitors and residents of Helensburgh.

Bruce and Nicola, of Puregreenspace, bought the property last year and since their “rediscovery” the premises was chosen to host the closing event of last year’s Mackintosh Festival, the annual celebration of the architect and designer’s work.

Nicola Jamieson said: “This is a champagne moment for us and comes after many months of hard work. We are lucky to have had an incredibly supportive family, and have also had tremendous support from the Helensburgh Community Council, Glasgow School of Art, Historic Environment Scotland and the CRM Society, all whose input has helped make the application successful. Experts have visited from all over the world over the past nine months and it is just the start of a very exciting development for Helensburgh.”

A charity is now being set up called Mackintosh Club Rooms, which has the sole aim of preserving and safeguarding the building. It will be driven by a board of professionals and Mackintosh experts.

Bruce Jamieson, managing director at Puregreenspace, said: “We are planning to build much of the new structure offsite so that assembly on site will be as quick and efficient as possible – keeping inconvenience to neighbours and the general public to a minimum.

“This is an extraordinarily exciting project and we hope to deliver architecture of the highest quality.”

Nicola Jamieson added: “The business and art collaborations that the Mackintosh Club have made are outstanding and a real asset for Helensburgh, this will grow year-on-year.

“Charles Rennie Mackintosh assets are a source of major public value and represent, in a tourism context, a significant economic opportunity as a unique selling point and key strength in Helensburgh’s positioning as a cultural tourism destination.”