Scotland's heritage lobby has demanded the Scottish Parliament calls in Foster and Partners' £400 million project for the Edinburgh Royal Infirmary.
Both the Architectural Heritage Society of Scotland (AHSS) and Historic Scotland have attacked the city council after it gave the mixed-use scheme planning permission last July.
They are furious because they believe the project is too tall - five of the towers will reach 12 storeys - and will unnecessarily damage many of the listed buildings on the site.
If the project gets the goahead, it will include a vast swathe of new office space, 650 homes, shops, and a host of leisure facilities. The developer claims the project will create 3,800 new jobs.
Opposition to the scheme has grown stronger despite the settling of a pre-planning dispute between the Royal Fine Art Commission for Scotland (RFACfS) and developer EDI Group over the design.
AHSS director Sean O'Reilly said the project in its existing form horrifies him. 'It is an atrocious scheme, ' he told the AJ.
'We are desperately pushing for a call-in, it would be an abomination if it went ahead as it is.
'Despite all the discussions about the designs while it was in the planning process at the council, there were hardly any changes, ' he said. 'The approach to the conservation of the listed buildings on the site and the surrounding world heritage site remains one of the worst I have ever seen, ' O'Reilly added.
The AHSS has the support of Historic Scotland. A spokeswoman said the agency - the Scottish equivalent of English Heritage - had lodged a series of objections with the Scottish Parliament. 'We object to the height of the towers, ' she said. 'We had agreed in the development plan that the towers could be up to eight storeys, but at least five are much higher.We want to discuss the project with the developers because we are unhappy with it as it stands.'
However, the objectors have lost the support of RFACfS director Charles Prosser. 'Architecturally it is so much better than it was when it was first lodged with the council, ' he said.
'We are pleased it has won planning permission.'
Foster and Partners was unavailable for comment.