Sir John Eliot Gardiner, 80, allegedly punched bass singer William Thomas following a performance at the Festival Berlioz in France, after the performer left the podium in the wrong direction.

The incident is said to have happened backstage, out of sight of the audience, but in front of some of the cast.

In a statement, Sir John said he "deeply regretted" the incident and understood "how much this has affected all the participants involved in this major project, which has been so dear to my heart".

He said: "I make no excuses for my behaviour and have apologised personally to Will Thomas, for whom I have the greatest respect. I do so again, and to the other artists, for the distress that this has caused."

The conductor said he had returned to the UK and withdrawn from future performances of the show, Les Troyens.

"I know that physical violence is never acceptable and that musicians should always feel safe," he said. "I ask for your patience and understanding as I take time to reflect on my actions."

Sir John will no longer take part in the BBC Proms in September, with his assistant, Dinis Sousa, taking his place.

A BBC spokesperson said: "Sir John Eliot Gardiner has decided to withdraw from the performance of The Trojans at this year's BBC Proms. We are grateful that Dinis Sousa will step in to conduct the performance on 3 September."

The broadcaster is investigating the matter, saying it takes allegations of inappropriate behaviour seriously and is "currently establishing the facts about the incident".

Classical music news site Slipped Disc first reported the alleged assault, saying it had received multiple reports.

Read more on Sky News:
Two arrested over fire at Britain's 'wonkiest' pub
Spanish FA president faces disciplinary proceedings over unwanted kiss
Ex-teacher's life 'torn to pieces' by pony hitting case

Representatives for Mr Thomas confirmed an incident took place on Tuesday but said he was looking forward to future performances.

"All musicians deserve the right to practise their art in an environment free from abuse or physical harm," the representatives are quoted as saying," they said.

Sir John, who is founder and artistic director of the Monteverdi Choir and Orchestra, has won two Grammy awards throughout his career and received more Gramophone Awards than any other living artist, according to the choir's website.

He has conducted many of the world's leading orchestras, including the Vienna Philharmonic and the London Symphony Orchestra, and operas at the Royal Opera House in London and at Teatro alla Scala, in Milan.

In May, during a pre-service programme, he led the Monteverdi Choir and English Baroque Soloists at Westminster Abbey for the King's coronation.

A spokesperson for the Monteverdi Choir said: "We continue to look into the events that occurred on Tuesday evening. Our values of respect and inclusivity are fundamental to us as a company and we take seriously the welfare of all our performers and employees.''

Sky News has contacted the festival for comment.