Reiach and Hall Architects and Purcell will undertake the addendum to the Strategic Outline Business Case (SOBC) for the rebuild.

Set to be published in early 2025, the SOBC Addendum will identify the appropriate route to delivery of the faithful reinstatement of the A-listed building, which was significantly damaged in a 2018 fire.

The GSA said the Addendum will ensure it can make “evidenced-based decisions, ensuring the Mackintosh Building is successfully rebuilt as a working school of art and contributes to the regeneration of Sauchiehall Street and Glasgow city centre”.

It added: “The combined team will commence work immediately and, with cost and economic consultants, robustly test the GSA’s previous assumptions, costs and economic impact, timelines and approaches to delivery of this significant project.”