TONIGHT'S spectacular international opening concert for the Celtic Connections arts festival in Glasgow has been cancelled at the eleventh hour, causing embarrassment for organisers and the city.

In the 13th year of what is now one of Europe's most popular traditional music festivals, the organisers said the opening performance at Glasgow Royal Concert Hall involving Carlos Nunez, Spain's foremost champion of Celtic music, and the world renowned Catalan theatre group, La Fura dels Baus, would not be held due to "technical reasons".

The organisers did not elaborate on the reasons. One source suggested it could be the stage was too small for the theatre group's large-scale performance, while another observer noted that almost a dozen other events advertised in this year's official Celtic Connections brochure have had to be cancelled or rescheduled.

Nunez, a Galician piper, has been a regular performer at the festival since it began. La Fura produced the breathtaking opening ceremony of the Barcelona Olympics in 1992, the live broadcast of which was watched by more than 500 million viewers worldwide.

Glasgow Cultural Enterprises, organisers of Celtic Connections, said a decision was taken at six o'clock last night to cancel the opening event, for which almost 1400 of 2000 tickets, priced at GBP16 or GBP18, had been sold. The organisers posted news of the cancellation on their website, and were also trying to e-mail and telephone ticketholders to tell them of the cancellation.

The organisers expressed "deep regret". In a statement, they said: "On Friday, January 6, we were informed that due to technical reasons, La Fura dels Baus could not bring their proposed show in its full capacity to the Glasgow Royal Concert Hall.

"As this was a completely integrated performance with Carlos Nunez, which was set to be both visually and musically spectacular, all possible avenues were pursued to try to programme an opening event of equal magnitude.

"Unfortunately this could not be achieved to the level we desired to ensure all audience members would be satisfied. We apologise for the inconvenience and will refund all customers."

Other events cancelled this year include The Songs of Ian McCalman, scheduled to be held next Tuesday in the Strathclyde Suite, which was to have featured artists including Barbara Dickson and Isla St Clair, and Deacon Blue, scheduled to perform on Friday in the main auditorium, but whose tickets never went on sale.

Celtic Connections, which runs until January 29, had hoped to stage 411 events and attract more than 1000 artists. More than 100,000 people from around the world attended the event last year.

A Torchlight Procession to mark the opening day, from George Square to the Concert Hall steps, led by Liz Cameron, the lord provost, and beginning at 4.30pm, will proceed as planned today.