The world's most prestigious arts festival might have to "drop down a division" if austerity hits its funding, its new artistic director has warned.

Fergus Linehan, who has unveiled an eclectic and innovative 2015 Edinburgh International Festival (EIF) programme, said Edinburgh and Scotland needs to discuss what kind of event it wants at the heart of its festival season: one capable of affording large scale operas, concerts and orchestras - or not.

Speaking in stark terms, Mr Linehan said: "It sounds like an institution whinging about not getting money, but it is actually asking a question about what kind of festival Edinburgh wants to have.

"That is a legitimate question - people could say 'we want something different' - but it is a gentle unravelling of what has been achieved over 68 years if you start to roll backwards [financially].

"It's a quality question, it is as simple as that - you either choose to have them or choose not to have them."

The festival is in the last year of a funding deal with Edinburgh City Council worth £2.3m this year, and recently received three year funding from Creative Scotland, also worth £2.3m this year.

Since 2008/9 has received £1.5m from the government's Expo Fund, including money this year for a new staging of Alasdair Gray's Lanark.

The festival's total cost this year is around £11.2m, with the EIF hoping to earn in the region of £6.2m.

Large scale projects this year include the opening free event at the Usher Hall, The Magic Flute by Komische Oper of Berlin, Antigone starring Juliette Binoche, Lanark by the Citizen's Theatre, and performances by the San Francisco Symphony and the Oslo Philharmonic, among others.

Linehan said he felt positive about ticket sales for this year's festival, which runs from August 7 to 31, but the "fly in the ointment" could be restricted or standstill funding from public sources in the future.

The Irishman said: "We have a fantastic family of donors, and they continue to be fantastic.

"But the fly in the ointment is what is going to happen in public finances in the next few years.

"I don't think anyone wants to damage the festival, but the fact is, what we are mandated to do, and what it is understood that we do, exists at a level which is unprecedented - we only present work on a level that we see in New York, Paris or London.

"But there is no cleverer way of being able to do really large scale work of this style without the funding."

He added: "It is a bit like the football club that just cannot buy the players anymore - it doesn't matter who the manager is, that's just the way it is at the moment.

"We either have to decide whether we are going to drop down a division, and manage it in that way.

"You either make the statement that you come here and see the world's best orchestras or not - there are either there or they are not."

Linehan said that with theatre you could be "entrepreneurial" about funding theatre, and "big outdoor events" can generate corporate sponsorship, but "if you really want to commission really major work - you can either afford it or you can't."

He added: "I think the most important thing for Edinburgh is to be honest about what its promise to the world is.

"I will be here for however many years I am here, but really the ownership of the festival exists within Edinburgh and it is a question of what decision is going to be made about what the festival is going to be.

"It's not like anyone is saying 'strategically we would like to reduce the capacity of the festival to programme in this way' - no one is saying that.

"It's a strange one because I am really positive about being able to develop other areas of this programme and bring other people on board, but the areas I can develop are the areas like the music in The Hub or theatre - but if the foundation starts to shake, no [sponsor] is excited by the idea of coming in and replacing funding cuts."