"Bond 25" is scheduled to arrive in UK cinemas on 25 October 2019 and open in US cinemas two weeks later.

But the film may not now be released "until late 2020", according to the Hollywood Reporter's unnamed sources.

The Oscar-winning director's shock departure earlier this week was attributed to "creative differences".

According to The Telegraph, those may have included Boyle's purported wish to cast Polish actor Tomasz Kot as the film's main Russian villain.

Kot, 41, can currently be seen in Pawel Pawlikowski's film Cold War, which had its premiere at this year's Cannes Film Festival.

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The Telegraph also claimed the film's producers had concerns over the script's focus on current political tensions with Russia.

A spokeswoman for Trainspotting screenwriter John Hodge, author of the script in question, confirmed this week that he was also no longer involved.

MGM and Eon, who produce the Bond films, declined to comment.

Boyle reportedly wanted Tomasz Kot to play the film's villain

Filming had been due to start in December at Pinewood Studios in Buckinghamshire, with Daniel Craig reprising his role as Ian Fleming's iconic spy.

David Mackenzie, Yann Demange and Joe Wright are among the film-makers who have been tipped to take over the director's chair.

With the exact reasons for Boyle's departure still unclear, people previously involved in the Bond films are being asked for their thoughts on the situation.

These include actor Jonathan Pryce, who is quoted in the Daily Mail as saying that the producers parted company with Boyle because "they obviously couldn't take a socialist Bond".

"There are the Dannys of this world and then there are people who do the blockbusters," continued Pryce, who played the villainous Elliot Carver in 1997's Tomorrow Never Dies.

 Jonathan Pryce played a nefarious media mogul in Tomorrow Never Dies

Boyle has never concealed his left-leaning sympathies, though he declined to identify himself as a socialist in a 2013 interview.

His opening ceremony for the 2012 London Olympics featured a Bond-based short and a set-piece tribute to the National Health Service.