THE "poisonous" rhetoric of Brexit talks could seriously damage the world's biggest arts festival, its artistic director has warned.

Edinburgh's International Festival (EIF) celebrates its 70th year in 2017, but director Fergus Linehan said Britain's European divorce has presented serious challenges for the renowned event including a danger that more venomous debate could repel countries from helping to bring their artists to the festival.

Mr Linehan suggested foreign governments, many of whom encourage, or provide financial support to take their homegrown productions to the festival, could be deterred if the public debate becomes even more rancorous.

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"Anything that would slow down tourism would be very, very detrimental to the Festivals," he said.

"There is a certain amount of this that is symbolic - you would hope that countries that would support their artists to come and perform in Edinburgh and still regard it as a priority country.

"Countries consider the festival to be an important place for their work to be seen, which is always tied into diplomatic priorities as well - and where we sit in that is going to be very important.

"This whole question of the UK as a welcoming, open place - it is important that is maintained.

"And the next three years as we work our way through this, you just hope that the rhetoric does not get poisonous."

Echoing comments from Donald Shaw of Celtic Connections, the festival director insisted that the volatile value of sterling has already made programming decisions more troublesome ahead of its historic year.

Mr Shaw had revealed how he had been forced to trim American acts he wanted from the forthcoming Celtic Connections festival because of the slump in the pound.

And Mr Linehan, who has been EIF chief since 2014 after successful stints with the Sydney Festival and Dublin Theatre Festival in his native Ireland, said the sinking sterling has taken a "big bite out of our spending power".

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"The prosaic stuff is that our currency up to 20 per cent down in its value, depending on which currency you are talking against, since say, November 2015, and that is just a reality, and it means our spending power has gone right down," he said.

"Right now, we are at the very practical stage [for Edinburgh International Festival 2017] where the wheel hits the road, and deciding what we are doing, so we are feeling that.

"The other practical thing is that it has thrown up a great deal of uncertainty in planning - where you ask people, people theoretically will do long term planning, but having been in a 'wait and see' pattern for a number of reasons, we are once again in a 'wait and see' moment again.

The festival chief's warning comes as a Creative Scotland report highlighted fears among Scottish acts that they could miss out on Europe's £1 billion cultural funding pot in the wake of Brexit as well as concerns about fresh travel barriers for international acts coming to Scotland.

With a fifth of the workforce at the National Galleries of Scotland and Scottish Ballet hailing from Europe, there are fears over the loss of international talent from Scotland's cultural landscape.

But despite the devaluation of sterling, Mr Linehan said Brexit does not necessarily mean a parred down Edinburgh International Festival in 2017 but suggested areas of the programme could be affected, including discounted tickets or his efforts to expand the geographical reach of the festival.

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He said: "There is a question of what does any one year of salami-slicing [to the budget] do? It makes some access issues harder, you have to start pushing earned revenue, and that is always challenging, because you are always trying to protect those areas where you do discounting, or where you are tying to push out the festival in terms of geography - things that are not necessarily high profile, but are important.

"I don't even know you could call it contraction, because scale could be in terms of quality, it could in terms of the breadth of access, how geographically representative you are, there are other ways of judging it, but it does just make it harder."

The Edinburgh Festivals as a whole are of considerable economic benefit to the Scotland, as well as cultural - a recent impact study said they attract 4.5m people, and generate £280m in Edinburgh and £313m for Scotland a year.

The festivals also position the city as a leading international destination, with 94 per cent of tourists stating that the Festivals are part of what makes the capital a special place to visit.

Mr Linehan suggested that the cultural world needs to look harder at the reasons behind the Brexit vote.

He added: "I think there is a battle royal raging, my own feelings are neither here nor there, but it is the reality but I think everyone has to ask themselves the questions around that globalisation has been better for some people than for others, and that is a reality."

Mr Linehan said the apparent political trend of "battening down the hatches" and looking inward was antithetical to the movement that inspired the creation of the Festival in 1947.

He added: "It is certainly interesting times. I think it is a time that we really need to think very carefully about what is going on. I do think if you look at the aspirations around 1947, around internationalism and Europeanism, then you do have to ask yourselves some questions about where it has led for some people.

"I don't think it is helpful to call people racists.