A controversial plan to turn the iconic old Royal High School in Edinburgh has been recommended for refusal by planning officials.

Developers Urbanist Hotels and Duddingston House Properties have said the proposal would see the A-Listed Thomas Hamilton building on Calton Hill become a "world class" facility.

A report presented to go before councillors said the plan would have a "significant adverse impact" on the site.

A £35m rival plan to the £75m hotel proposal for a music school already has planning permission.

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Planning officials said in their report on the hotel plan: "The proposed interventions to the listed building would have a significant adverse impact on the architectural integrity, composition and special character of one of the UK's finest listed buildings.

"Alternative consents, for the redevelopment of the building into an international music school, exist."

The report said the plan does not comply with national guidelines on historic buildings, the city's development plan or Edinburgh planning guidelines.

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The report concludes: "Proposals for demolition do show that the luxury hotel would provide economic benefits to the city.

"However, the proposals fail to address the requirements of HESPS (Historic Environment Scotland Policy Statement 2016).

"Further, the demolition cannot be granted in isolation as test c) of HESPS is inextricably linked to the economic growth generated from redevelopment proposals.

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"These proposals are considered unacceptable."

Also known as New Parliament House, the 19th century building was previously intended to house the Scottish Parliament.

A decision on the hotel plan will be made next week.

The planning application seeks permission for "refurbishment (external/internal), alteration and extension of principal former Royal High School buildings to include works to north elevation to create new door openings/new corridor links, demolition of former Lodge, Gymnasium Block, demolition of two curtilage buildings - former Classroom Block and Luncheon Hall - demolition of existing gates/wall (in part) to facilitate development of a world class hotel".

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David Orr, chairman of Urbanist Hotels, said: “We need to be very clear about what is now at stake for the very future of the Old Royal High School.

“Our revised proposal is the result of 18 months intensive work and considerable investment in order to fulfil our contractual obligation with the council.

"During this time we have taken time to listen to a wide range of stakeholders and heritage experts and taken their views on board.

“We now have a design solution which not only protects and promotes the magnificence of Hamilton’s centrepiece building but also has a viable and long-term investment plan in place to maintain it as part of the city’s living and breathing heritage.

"We are responding positively to the requirement by the council, following ratification of our contract in 2014, to revive a building which has been allowed to slip into a state of disrepair and neglect for more than 50 years.

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“Hamilton’s masterpiece has been publicly owned since 1829, but never publicly accessible.

"Our design will restore and regenerate this national treasure with a new use as a world-class hotel for the people of Edinburgh and beyond. Heritage and conservation are central to our plans.

“This is the only proposal that can realistically guarantee the future of the Hamilton building – both architecturally and financially.

"Without it, we risk another 50 years of disrepair and misuse, which would be catastrophic for both the building and the city.

"I am confident that those who genuinely care about Edinburgh’s future, and can look through the emotional rhetoric and see the hard facts, won’t let this happen.”