The Scottish National Gallery construction project's completion has been delayed after the first lockdown and "unexpected defects" at the site hit progress.

Set to reopen to a revised time next year, works are now expected to be completed and the new gardens-level galleries open to the public by the end of 2022.

It is also expected to mean additoinal costs for the £22 million poject.

The gallery said the defects outlined earlier this year are in the 1970s building which sits beneath the original nineteenth-century structure.

It includes damp penetration and inadequate drainage in and around the site.

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The gallery said that halting work during lockdown along with the complex and changing nature of the construction requirements have led to revised project timescales.

Sir John Leighton, director-general of the National Galleries of Scotland, said: “We always knew that the Scottish National Gallery Project would be a complex endeavour, but that never diminished our desire to deliver the new space that our visitors deserve.

"Working underground on a World Heritage Site that comprises an iconic nineteenth-century building with modern additions from the 1970s located above one of Edinburgh’s busiest train tunnels is, of course, challenging.

"The Covid-19 pandemic has added a further layer of complexity, with the closure of the site during lockdown and now the introduction of measures to accommodate social distancing. Any associated additional costs are being worked through diligently.  

"While we recognise this delay may be disappointing, we also want to stress that the wait will be worth it. We will deliver a world-class facility for showing Scotland’s distinctive artistic heritage in a whole new light, and at a time when we all hope the Covid-19 pandemic will be receding. We intend for our new galleries to be a focal point for cultural renewal, a place to discover the joy and wonder that art can bring to us all.”

The first phase of the National Lottery Heritage Fund and Scottish Government-funded project was completed in 2019. However, the overhaul of the gallery has suffered a series of problems since the project was first announced in 2015 with a £15.3m price.