Scotland'S international festivals are under threat, with thousands of performers likely to be kept away by visa controlsbeingintroducedbythe Home Office.

The Sunday Herald understands directors from each of the Edinburgh festivals have already met to discuss the potential impact of the new British immigration system, starting in 2009.

Further meetings are planned with the Home Office as organisers fear acts from around the world would be turned away under the new scheme to replace work permits. It is estimated around 3000 performers at the Fringe Festival alone would be affected, despite the event having "permit-free status".

Under the new, points-based system, designed to attract the "brightest and best" to the UK, anyone from outside the European Economic Area (EEA) would need to be sponsored by their future employer or an educational institution. The tier structure exempts only "highly skilled migrants", classed as Tier One, from sponsorship, with artists and writers more likely to be classed as Tier Five - "temporary creative or sporting workers".

They would require the organisers or affiliates, such as promoters or government-funded bodies to apply on their behalf. But with possible sanctions should conditions of entry be broken, not to say impossibly tight timescales and the logistical nightmare of applying for every performer, festival organisers cannot afford to act as sponsors.

Catherine Lockerbie, director of the Edinburgh International Book Festival, who was unable to attend the directors' meeting, described the matter as a very serious issue'.

She said: "Visas are an issue for all of us. Last year I had people from 35 different countries and they all required visas to come to the UK. It seems like a hammer to crack a nut."

In 2005, the celebrated Zimbabwean writer Chenjerai Hove threatened to pull out of the Edinburgh International Book Festival after he was refused entry to the UK en route to giving a lecture at Edinburgh University.

In the same year, footballers from five African nations were refused entry to play in the Homeless World Cup in Edinburgh over fears they would not return home.

Lockerbie, who is obliged to supply an official letter of invitation for every performer coming to the book festival, added: "The worry is people may be forced to tailor their aspirations because of the legislation and I would not be intending to do this. We are the most international literary festival in the world and that is what marks us out."

FaithLiddell,directorofFestivals Edinburgh, a post created in December to ensure Edinburgh stays ahead of growing competition, described the legislation as a serious problem."The international quality of our programmes is essential for us to compete," she said.

A spokesperson for the Home Office said the legislation was not designed to impact upon festivals butwas "just another check" to prevent abuse.