The producer of the film, Monty Python and Holy Grail, who won a High Court case against the Pythons over unpaid royalties, has expressed his regret at how the legal battle has destroyed his friendship with John Cleese, Michael Palin and the rest of the comedy team.

But Mark Forstater, who helped to bring the Arthurian spoof to the screen in 1975, said he was glad to be able to move on and focus on new projects, including the publication of a book on the Holocaust.

Speaking after his court victory, he revealed that he had never expected to face his erstwhile colleagues in front of a judge.

“I didn’t think they would want to go to court,” he said. “I was very surprised.”

The American-born producer’s relationship with the Pythons goes back more than half a century to when he met the group’s future animator, Terry Gilliam, in New York and shared a flat with him.

But he regretted now that “the friendship is gone”. Although he had not had much contact with the Pythons in the past 20 years, he said: “Michael Palin was someone I could always write to. When I saw Gilliam, we’d have a chat. But you can’t just do that if you are going to be opponents in court.”

Mr Justice Newey agreed with Mr Forstater’s claim that he was entitled to the same share as each of the six Pythons to the spin-off proceeds from the film.

Until 2005, Mr Forstater had received his one-seventh share, but then the Pythons argued that this had been a mistake and he had been entitled only to one-fourteenth.

The royalties owed to him could amount to £300,000 — mostly from Spamalot, the lucrative musical spin-off from The Holy Grail, which opened on Broadway in 2005.

Mr Forstater — who was dubbed “the seventh Python” by a lawyer acting for the Pythons at the time of the film — said: “Eight years is a very long time. At times, there was tremendous stress. I had to spend a lot of money and take a huge risk in going to court.”

He is looking shortly to complete a film now in post-production, a psychological thriller called The Power, and in September he is due to publish I Survived a Secret Nazi Extermination Camp — the reprint of a testimony of Rudolf Reder, a survivor of Belzec camp.

It was an account “of one man’s survival through hell,” he said. “You only survived if you became a worker. He was an engineer. He could fix the ovens, he could fix the engines that produced the gas.”

The book contains a memoir from Mr Forstater about his family during the Holocaust and his attempt to find out what happened to them.