Scotland could lose a pool of vital cultural talent if Hard Brexit repels EU nationals, the leader of Scotland's national galleries has said.

National cultural institutions in Scotland have a significant percentage of non-UK EU nationals in their staff and the uncertainty over their future post-Brexit is a major concern.

Around 20% of staff at the National Galleries of Scotland are non-UK EU nationals and other national arts institutions also have significant numbers of EU nationals in their workforce.

A fifth of Scottish Ballet's staff are non-UK EU nationals, while 12% of the Royal Scottish National Orchestra are in that category.

Around 11% of the National Museums of Scotland's employees are EU nationals, and 8% of the National Theatre of Scotland workforce.

Sir John Leighton said that two major concerns of Brexit for the visual arts world are the implications for the movement of people, and the movement of objects.

While Nicola Sturgeon, Scotland's First Minister, has repeatedly said EU citizens are welcome in Scotland, the overall picture is less clear, with Theresa May, Prime Minister, refusing to guarantee the rights of EU citizens in the UK.

Sir John said: "We would subscribe to the view that the ease of movement has been of huge benefit to the creative sector.

"It is not just curatorial staff, but other public policy areas such as finance and PR - we've benefitted from with a wide knowledge base, and of course, languages.

"They are worried about the long term. I'm worried for them, and whatever bland re-assurances you can give them, no one has said you can definitely stay, and that has an affect on people.

"I know from my own experience that there is a certain insecurity about being an ex-pat [when he was a director of the Van Gogh Museum in the Netherlands]. We have certainly benefitted from a wider pool of talent and expertise."

Galleries and museums are currently exempt from tariffs on the loaning of art to and from Scotland and other EU countries.

Hundreds of major art works are loaned, and are received as loans, every year at Scotland's major galleries.

The National Galleries of Scotland (NGS), for example, loaned 800 works of art to other galleries in the last year, and received 1200 in return.

Loaning and borrowing works of art is the the bedrock of 'blockbuster' summer shows such as the Surrealist and Impressionist shows being staged this summer in Edinburgh.

However, post-Brexit, gallery directors and gallery registrars - who manage the flow of art to and from galleries - fear being outside the EU will lead to extra charges and bureaucracy which could stifle the staging of top-class exhibitions.

The extra costs and drain on resources will hinder collaborations with other major galleries, it is feared, and damage the free flow of art between Scotland's galleries and abroad which is key to major international-quality shows.

Kathy Richmond, the chair of the UK Registars Group, said she was "very concerned" about both a possibility levying of charges on loaned art as well as the extra resources required to organise exhibitions, with costly and time consuming bureaucracy, after Brexit.

Sir John added: "The movement of objects is far more complicated than the movement of people.

"There is a web of regulations, local, national and international, but through all that complexity, a big part of being in the EU has eased the movement of objects: there are streamlined processes for the EU.

"If that does close, there will be extra bureaucracy and extra cost, and everyone knows that in the near future there is not more money sloshing around.

"In the long term, who knows what the implications are, but there's certainly the real basket of spanners being thrown into the situation."

He said he was personally "determined" to counter the effects of Hard Brexit by continuing "cultural engagement."

"We will continue to build bridges and not walls," he said.

"I hope it does not effect the exhibitions we have, I have a programme going forward for the next year and I hope that we will keep going and for years after that.

"For all the demoralising effects of uncertainty, we will try to not become risk averse.

"Hopefully working together, with other galleries, we can re-double our efforts to make sure we are not scared off from the working at the scale we are accustomed."