In recent years, artists like Prince, Billy Joel and Blondie have used the US 1976 Copyright Act to regain control of their work.

However, Duran Duran recently lost a similar case before the UK High Court, which ruled that the contracts they signed in the UK took precedence over their rights in the US.

The Beatles signed away their publishing rights at the start of their career, on the advice of their manager, Brian Epstein.             

Under UK copyright law, music publishing companies can control the copyright until 70 years after the artist's death.

Sir Paul is concerned that Sony/ATV Music Publishing will use Duran Duran's loss of the High Court case to challenge his attempts to obtain The Beatles' back catalogue. Through legal action, Sir Paul is trying to ensure that Sony does not stand in his way by accusing him of a breach of contract or publishing agreement. He is seeking a declaration from the court that he can reclaim his songs, as well as legal costs.

The legal documents filed by Sir Paul state that: "Rather than provide clear assurances to Paul McCartney that the defendants will not challenge his exercise of his termination rights, the defendants are clearly reserving their rights pending the final outcome of the Duran Duran litigation".  In addition, it is stated that Sir Paul wants "quiet, unclouded title to his rights".  

Sony/ATV said it was "disappointed" by the lawsuit, calling it "both unnecessary and premature". 

Unlike Duran Duran, Sir Paul has filed his legal case in America, but the verdict could have major ramifications for other British artists.

Songs in the Lennon-McCartney catalogue, composed between September 1962 and June 1971, become eligible for copyright termination in the US after 56 years. The first will be "Love Me Do", which could revert to Sir Paul in 2018 - but others, including "Come Together" and "Get Back", are not due to become available until 2025.

John Lennon's share in The Beatles' songs will not return to his estate because Yoko Ono sold the rights to his music to Sony/ATV Music in 2009, with those rights lasting the entire copyright's lifetime (70 years).