REBUILDING the Glasgow School of Art will be as complex as restoring Windsor Castle, a leading architecture expert has claimed.

The building, often described as Charles Rennie Mackintosh's masterpiece, was partially destroyed on May 23, 2014 when a blaze tore through the delicate structure.

Neil Baxter, secretary of the Royal Incorporation of Architects in Scotland said the task of rebuilding it will be even more difficult due to the limited number of master crafters available to work on the project.

Speaking ahead of the first anniversary of the fire, Mr Baxter said: "The rebuilding of the fire at Windsor Castle was the last biggie that required this level of expertise.

"You're talking about two buildings which really needed an absolutely accurate reinstatement of what was there and it had to be as good as it could be.

"You're looking for perfection...[With] Glasgow School of Art even more so. There are lots of palaces throughout Europe...there is only one Glasgow School of Art."

Mr Baxter said the feat facing assigned architects Page and Park will be even more difficult due to the limited number of artisans now working in Europe.

At the time the masterpiece was built, there were thousands of master craftsmen, carpenters and plasterers on the continent able to carry out the most intricate work on major projects.

Now only a tenth of the previous numbers of experts remain.

Mr Baxter said: "You're down to a few hundred people across Europe who will have these highly developed skills.

"They are not needed for most modern building projects. There are experts in restoration, there are some older skilled artisans and one or two apprentices coming through but the numbers are not there so it will be a very tough commissioning task.

"Glasgow at the turn of the 19th into the 20th century had some of the most highly qualified and able craftsmen and designers on planet earth because we had the ship building industry.

"The fitting out of ships had incredible expertise in carpentry, plaster work, metal work, everything was done to the very highest quality.

"Mackintosh drew on those skills to create the original building.

"That's what has to be replicated...It's not an easy gig but we have to be confident that a new generation of Glaswegians can do something as good as former generation."

Stuart Robertson, director of the Charles Rennie Mackintosh society, said other Mackintosh buildings throughout the city have actually seen a boost in visitor numbers since the blaze as fans look for alternatives to the world-famous library.

Mr Robertson said: "In the short-term, in the months after the fire, we were seeing an increase in visitors.

"It gave an opportunity for buildings like the Queen's Cross Church, which were lesser-known, to have their profile raised a bit.

"People were saying the library had been on their bucket list and were asking what else they could see.

"We were getting a lot more [visitors] at Queen's Cross which has a lot of what I would call the embryos of the art school and the library within the building. Ten years before the library you can see Mackintosh's thought processes happening inside the church."