Developers want to turn the old Royal High School into a luxury hotel.

Duddingston House Properties and Urbanist Hotels were behind the plans to turn the former school into a five star hotel.

Their controversial proposal for the A-listed building on Calton Hill was rejected by city councillors last month.

Lewis Ritchie, the council’s planning convener, described the designs as “abhorrent” and “ugly,” and said they were “almost universally reviled” by anyone who had seen them.

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The blueprints for the site, which has lain empty for close to half a century, drew a chorus of criticism from heritage bodies, elected representatives, and members of the public.

Now, David Orr, the chairman of Urbanist Hotels, told The Evening News the developer remained determined to find a future for the old Royal High School.

He said: “In line with our contractual agreement with City of Edinburgh Council, we remain wholly committed to delivering an outstanding scheme for the old Royal High School, reviving a building which has been allowed to slip into a state of disrepair and neglect for nearly 50 years.

“As such, we have advised the planning and environmental appeals division of the Scottish Government that it is our intention to appeal.”

Lawyers for the developers have already written to the government department advising them that an appeal will be forthcoming.

Ann Faulds, a partner at law firm, CMS Cameron McKenna Nabarro, emailed officials last Thursday to advise them that an appeal would be lodged “as soon as practicable,” once supporting documents had been gathered and a formal decision notice was received.

The original planning application for a hotel was refused by the council in December 2015.

It has since been appealed by the developers and is currently with ministers.

A spokesman for Mr Orr confirmed Duddingston and Urbanist intend to pursue that appeal alongside the new one.

A rival £35m proposal to relocate St Mary’s Music School across the capital to the neoclassical structure was granted planning permission last year.

However, the developers, led by Mr Orr, have insisted that their contract with the council to develop the site will not expire until 2022, meaning no other project can proceed.

Other correspondence received by the government’s planning and environmental appeals division indicates the contentious issue end up being the subject of a costly public local inquiry.

The building, designed by Thomas Hamilton in 1825, was vacated in 1968 when the school moved to Barnton. During the 1970s it was proposed as the site to house a devolved Scottish Assembly.

However, the 1979 devolution referendum did not result in an assembly and when the Scottish Parliament was finally set up in 1999, a new site was chosen.