ONE of Scotland's leading conservation architects today delivered a damning verdict on controversial plans for a huge site in the city's Old Town.

James Simpson said the Caltongate project would damage Edinburgh's World Heritage Site and that developers should "go back to the drawing board".

Mountgrange wants to bulldoze a block of 1930s tenements on the Royal Mile and demolish two other listed buildings to make way for a luxury hotel and conference centre.

Mr Simpson said the council had been wrong to "encourage" the London-based firm to expand on its original plans, which had been for a former bus depot in New Street. He said the developer appeared to have been "deliberately devious" with the council by dividing its plans into numerous separate applications.

Mr Simpson, whose plans to restore a derelict mansion house in Midlothian were featured on the BBC's Restoration series, said: "The case for demolition [of the tenement building] has not been made at all. It is in good repair, is structurally sound and is still in use for its original purpose.

"There is no doubt that the redevelopment of the old bus depot site at New Street is a good thing but I do think it is regrettable that the council has seen fit to encourage the developer to develop a wider area by knocking down listed buildings and a perfectly good tenement building on the Canongate.

"In a medieval town like Edinburgh, any development should be kept to a minimum but it has been profoundly misguided to encourage a development as big as this one is now."

Mr Simpson – a former board member of the Edinburgh World Heritage Trust, the Architectural Heritage Society of Scotland and the Cockburn Association – said demolishing the tenement would be against policies and guidance of Historic Scotland and the Edinburgh World Heritage Trust.

"It is my firm view that these applications contradict all the principles by which development in the World Heritage Site should be managed and controlled," he said. "They should be refused and the future of this extremely important site reconsidered."

The plans also involve the demolition of the former Canongate Venture school building, which is currently offices, and the old Sailors' Ark which was until recently a hostel for homeless people.

A Mountgrange spokesman said: "The detailed applications that we submitted earlier this year accord entirely with the Caltongate masterplan, which was unanimously adopted as supplementary planning policy for the area by the city council's planning committee last October.

"Mountgrange is working with the council to assess and respond to issues raised during the statutory consultation period. It is not our policy to respond to individual representations made in isolation, however we welcome all views."

As well as the hotel and conference centre, Mountgrange plans to create cafes, bars and restaurants and a new public square in its £200 million development on and around the site of the old bus depot, as well as 200 new homes.

Caltongate development