Two of Britain’s most distinguished actors are set to star in a £6million film ‘co-written’ by a leading figure of the Jihadi John apologist campaign group, Cage.

Sir Ben Kingsley and Emily Watson will be working alongside an award-winning team in ‘The Secret Evidence’.

Golden Globe-winning producer J Todd Harris is said to already be on board, and the film has commitments from Emily Watson, Sir Ben and Lily Collins.

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Actors Sir Ben Kingsley and Emily Watson are among stars to have signed up to the film that has been reportedly co-written by the Cage spokesman

Last night The Mail was unable to contact representatives of the stars, who are believed to have made the commitment to the movie long before the controversy surrounding Cage.

The film, which is supported by civil rights group Liberty, is thought to have been co-written by former terror suspect and Cage spokesman Cerie Bullivant.

He spent two years under a control order before eventually being exonerated, and the film is believed to be loosely based on his own experiences.

But Mr Bullivant’s involvement became an embarrassment for the movie after the unmasking of Mohammed Emwazi as Jihadi John. Last month Cage sparked outrage by defending the London-raised fanatic unmasked as the Islamic State butcher.

The group described Emwazi as a ‘beautiful and gentle’ man who was driven to radicalisation by MI5.

Promotion: The leaflet for the film showing Miss Watson, Saoirse Ronan and Sir Ben Kingsley

And Mr Bullivant railed for eight minutes about the treatment he had received at the hands of the security services ‘in very similar circumstances’ to those of Emwazi, suggesting it was the MI5’s actions which had led to the brutal killer’s radicalisation.

The former mental health nurse also claimed UK security forces harassed Emwazi to the point where he had ‘no options and position within UK society anymore’ in an official video for Cage.

He even went as far as suggesting an alleged assault on Emwazi by the police in 2010 could be directly linked to the beheadings. Speaking to the Islam Channel earlier this month, the 32-year-old said: ‘He was looking to get married, get a good job and settle down.

‘If that had happened, if our security forces had not had stopped him, would he be cutting off heads now?’ He added: ‘We have a two year picture of a man constantly…trying to move his life forward and we see a pattern of security services stopping that.

‘We even see a pattern of the police pinning him up against the wall and strangling him. This is a chilling simile when you look at what he ended up doing to other people.’

Cerie Bullivant is a former terror suspect and spokesman for the group Cage

Bullivant was in the spotlight again earlier this month when he stormed off in the middle of a live Sky news interview claiming a question on about his feelings on the beheadings was racist.

Now the filmmakers behind ‘The Secret Evidence’ appear to be trying to distance themselves from Bullivant – perhaps fearing that the link with him could damage their chances of securing the £1million still required to begin production this year.

The Mail has seen a document, which was presented to potential investors as recently as last summer, clearly stating that the film was ‘co-written by Cerie Bullivant’.

And an invitation to a high-profile event due to be held at the Chiltern Firehouse restaurant in London tonight to attract potential investors – which was sent out earlier this month – said: ‘It was co-written by Cerie Bullivant, who was wrongly sent to Belmarsh at 23.’

However, the next day the same invitation was sent out again – but with the line mentioning Cerie Bullivant deleted.

The film’s award-winning director Nicholas Racz admitted that the invite to tonight’s event was edited. He said: ‘Cerie generously said there was no reason for him to be mentioned. It was an association that wasn’t helpful to the movie.’

He added: ‘Cerie’s involvement was some five years ago where he was involved as a co-writer. This was before his involvement with Cage and the movie is not based on his life.

‘He has contributed to the script, absolutely, and he will still be paid for that if the film is made but it won’t be a significant amount of money.’

And Liberty director Shami Chakrabarti, who is helping to host the film’s fundraising event tonight, admitted Bullivant had ‘some involvement’ in the film.

She explained: ‘My understanding is that Cerie Bullivant is one of a number of stories that inspired this film.’

However she went on to say: ‘Whatever you may think of Cerie Bullivant, he did suffer a miscarriage of justice many years ago, and there will continue to be many more miscarriages of justice if we continue down this path.

‘Fiction is more powerful than anything and I really hope this is a great inspiring film exposing secret courts and secret justice.’