On screen, the stars of Celebrity Traitors viciously murder or banish their fellow cast members in a bid to win the show.

But when the cameras stop rolling, contestants on the BBC One show are still ‘at one another’s throats’ as the tension and ‘utter paranoia’ between them spills over into real life.

Sources say that unlike last year’s celebrity version of the programme, when the line up had fun and enjoyed it, this time it became extremely stressful behind the scenes.

Traitors insiders suggest that wrong decisions at the round table when two Faithfuls were sent home sparked the paranoid behaviour.

On Thursday, US actress Myha’la, star of BBC One’s Industry, was banished and on Friday, former Coronation Street favourite Julie Hesmondhalgh was sent home in a shock decision – rather than mathematician Professor Hannah Fry, a Traitor.

A show insider told The Mail on Sunday: ‘The tension is coming across on screen, but it was just as bad if not worse when the cameras stopped rolling.

‘It is a tense environment, and they are cut off from the outside world; it is hard for them to switch off even when they head back to their individual lodgings.

‘They were constantly thinking about the game.’

Pictured: The cast of this year’s Celebrity Traitors

Even funnyman Rob Beckett surprised his co-stars, with high energy behaviour which was at times hard for the others to deal with while filming in Scotland early in the summer.

The source added: ‘They were all making each other more stressed out. A lot of them just couldn’t hack it, I’m not sure what they thought they were signing up to.

‘One contestant really lost their nerve at one point and their co-stars were absolutely stunned.

‘And Rob, who is usually so funny, really struggled at points and surprised the others with his behaviour. They put it down to the fact that things were so tense.’

Another source said that some on the show, which also stars Ross Kemp, Miranda Hart, Maya Jama and Jerry Hall, struggled to remember it was just a game.

The pressure became so intense for comedian James Acaster, who was recruited as a Traitor in the second episode, that filming had to be paused.

The 41-year-old became ‘very anxious’ on set in Ardross Castle and some of the other contestants were forced to speak up and insist the cameras stop rolling.

BBC bosses later stressed that the welfare of contestants was a priority.

Viewers of the game show have watched as Acaster has become increasingly distressed on screen, repeating: ‘I’m not good at lying.’

The stand-up comic expressed his wish to remain a Faithful on the show.

Faithful Kemp – best known for playing hardman Grant Mitchell on EastEnders – has entertained viewers by becoming increasingly paranoid when other cast members touch him.

And it wasn’t just the celebrities feeling the stress.

During filming, their teams were kept completely in the dark and had no contact with their clients until they exited the game.

Agents and publicists have no say in what is shown and can only hope their clients get a good edit.