Work is finally under way on the long-awaited transformation of the Scottish National Gallery in the city centre.
But its completion date has already slipped from the summer of 2018, even though the gallery is expected to remain open to the public throughout construction work.
That will almost certainly mean some disruption at the site – which currently gets 1.4 million visitors a year – during two Edinburgh Festivals rather than one.
The £16.8 million project will triple space for some of Scotland’s most important art treasures by converting office, print room and storage space.
Critics have long been dismayed that work by the likes of Allan Ramsay, Sir Henry Raeburn and Sir David Wilkie have been hidden away in a “dingy” and little-known basement area.
Designed by William Henry Playfair, one of Edinburgh’s most celebrated 19th-century architects, the national gallery dates back to 1859. A £32m project to link to it to the neighbouring Royal Scottish Academy building was completed in 2004.
The new project, which has been at least four years in the planning, will also lead to the creation of a new entrance from Princes Street Gardens.
The Scottish Parliament has given special approval to the project to allow the National Galleries of Scotland to take control of part of the gardens which were previously designated as “common good land”.
The city council has given its final approval to the project, saying that the loss of open space in the gardens is “minimal”.
A report for the planning committee said: “The galleries already have a presence in the gardens. The purpose of the scheme is to improve the cultural, leisure and educational facilities, and is complimentary to the gardens, rather than for commercial use. The extension is therefore justifiable in this instance.”
Although preparatory work will be carried out at the gallery over the next few months, the start of construction work on site – which was expected to begin this year – has been put back until the spring of 2017.
Galleries official today said the new galleries would be ready to open in “early 2019”.
A spokesman for the national galleries said: “As with any major project, the programme length can only be estimated in the early stages. Now the design has advanced to a more detailed stage, and following discussions with the contractor, we have a better understanding of the timings required for this project so we can give a stronger indication of a target opening period.”
Michael Clarke, director of the Scottish National Gallery, said: “I would like to thank the city council for their support of this project which will truly transform this site at the heart of Edinburgh and enable new audiences to enjoy the magnificent Scottish art collection.”