The Master of the Queen’s Music was “delighted” yesterday after his former manager was jailed for 18 months for defrauding him of more than £500,000.

Sir Peter Maxwell Davies hinted that the “horrors” of the ordeal may even inspire a musical composition.

Michael Arnold, a friend and business associate of the composer for 30 years, first appeared at Kingston Crown Court, South London, on October 20 but the case was adjourned for further mitigation and sentence.

A charge against Arnold and his wife, Judith, of stealing £447,000 from Sir Peter was dropped when the pair pleaded not guilty. Arnold had previously admitted false accounting involving £522,333.

Sir Peter was temporarily unable to compose and had to borrow from friends. He said: “I am delighted at the sentence. I wish I had never met Michael Arnold and I am glad he has been jailed. I went through some very difficult times because of him and I am glad it is now resolved and I can move on. I may even set it all to music. Who knows? That would be the ultimate revenge.”

Arnold was arrested in 2007 and charged — together with his wife — in October last year. The missing money is said to have included the composer’s £15,000 annual retainer for his royal duties and it is thought to have been spent on online gambling.

Arnold, 76, and his wife, 73, looked after the composer’s affairs for 30 years. Sir Peter’s music is even catalogued in what he calls “J Numbers”, named after Mrs Arnold, and he has dedicated pieces of music to the couple.

Sir Peter, who lives in Sanday, one of the Orkney Islands with his partner, Colin Parkinson, is reported to have received a substantial settlement from the Arnolds last year after starting a civil action in the High Court.

He said recently: “I was very unhappy and I stopped writing for six weeks. But you have to move on. It was hard to cope with because I had no money, and I had to borrow £10 or £20 from this or that person on the island just to get basic shopping. But now the royalties are coming in, which is wonderful.”

The police investigation looked at Sir Peter’s private company, Max-Opus, one of the first classical music download sites on the internet. Sir Peter set up the service with the Arnolds in 1999 and the couple were appointed directors in 2000. Part of the civil settlement is believed to have involved Sir Peter having complete ownership of the website.

Sir Peter has conducted some of the world’s finest orchestras, including the BBC Philharmonic and Royal Philharmonic. His 75th birthday earlier this year is presently being marked in Glasgow with a celebration of his work organised by the Royal Scottish Academy of Music and Drama.

In total seven orchestras and ensembles will perform 18 of Sir Peter’s works until Sunday.

Times Recommends

• How I lost the gift of joy for a while
• Why Ann Widdecombe has got it wrong
• Alas, it’s the end of the road for petrolheads