The selection panel considering proposals from five shortlisted architects recommended the Dutch practice to transform the Edwardian venue into a £20 million major arts hub last week.

However the choice was criticised by the Royal Incorporation of Architects in Scotland (RIAS) which said the recommendation highlighted a “variance from the procedure set out in the bid documents”.

Scoring criteria to assess the shortlisted entries against the brief, which were developed by RIAS and agreed with council officers, were weighted 80% of the scoring criteria attributable to architectural quality and 20% to the fee price. The relatively high ratio of quality to price was agreed “to reflect the importance of the design concept to the council”.

A report recommending the appointment of Mecanoo to the project show that the firm initially came third in the competition, based on the combined scores for quality of design and proposed fee.

The practice did, however, comfortably top the shortlist based on design alone.

Council officers felt the low marks on fees had disproportionally weighed against the firm, and that Mecanoo’s design concept “is the only one which, on the basis of the estimated construction cost, can be delivered for the available project budget”.

Backing the recommendation, the local authority said that the proposal from Mecanoo best meets the core requirements from the competition brief.

Following a meeting of the full council yesterday, a spokesperson told Scottish Construction Now: “Today councillors agreed to recommend to the East Central Scotland HubCo that Mecanoo be added to their list of approved architects for the redevelopment of the City Hall. This is a key Tay Cities Deal project which is part of the wider strategy to develop a cultural and creative industry corridor along the Tay.

“The project brief had three core requirements, a building which delivers the operational needs of a major museum attraction; responds sensitively to the surrounding public realm; and is affordable and deliverable within the £20m budget, £11m of which represented the construction cost element.

“Mecanoo’s design best met these core requirements of the brief in terms of quality and the ability to be delivered within the council’s agreed budget for the project. This design also attracted the greatest support from local residents and businesses and taking into account initial views from Historic Environment Scotland which is a statutory consultee.

“As part of our wider plans for the transformation of Perth, the council remains committed to delivering an outstanding cultural venue and we are looking forward to working with all our partners on this exciting next phase.”

The council voted in June to bring Perth City Hall back into public use with the vision of increasing the city’s capacity to display collections of national significance, house major touring exhibitions and feature national and oversees loans.

The competition challenged architectural firms to come up with a grand vision for redeveloping the building into a cultural attraction capable of bringing visitors to the city from around the world.

Austin-Smith:Lord/ MVRDV, Hoskins Architects, LDN and Richard Murphy Architects were shortlisted alongside Mecanoo following a design competition which attracted global interest and over 70 initial expressions of interest.

In its submission, Mecanoo said: “The project endeavours to create a new gateway to Perth; to its history and its pride. Perth City Hall has been under a ‘dust blanket’ for many years however its grandeur and resonance within the hearts and minds of the community has meant that it has not been forgotten.

“Our scheme proposal aims to re-activate Perth City Hall by a number of ‘light touch’ interventions that open the building up to the public realm at ground level (The Vennel and the café/bar) and provide a flexible platform in which to best display Perth and Kinross Council’s permanent and temporary collections.

“The design is about transparency, permeability, accessibility and creating an interactive environment for all.”

BAM Construction, which was appointed by hub East Central Scotland to redevelop the building, is expected to start work in 2019, with the grand opening scheduled for 2021.