Caleb and Tracy have started an affair (Picture: ITV)

Since Caleb Milligan (William Ash) arrived in Emmerdale last Christmas he’s been no stranger to controversy. For a start he came with a secret agenda – to take Home Farm and everything else Kim Tate (Claire King) owns away from her as revenge for her part in his father Frank Tate’s death.

But viewers have recently seen Caleb embarking on a storyline that took even the actor who plays him by surprise – his affair with Tracy Robinson (Amy Walsh).

‘It was a bit of a shock for me that they were going to be getting together,’ William Ash told us of his first reaction on hearing about the storyline.

At the same time, he said that it made complete sense and had even been hinted at in earlier episodes.

‘In some earlier scenes when my character first met Tracy, when he was getting involved with ideas for the nursery and all that stuff, there was a bit of sexual tension between them,’ he recalled.

‘There was a slight frisson of something, whether she was attracted to the amount of money he had and the amount of doors he could open for her.’

Viewers first saw Tracy and Caleb kissing in the week of episodes where Lydia (Karen Blick) interrogated the Dingles about their whereabouts when rapist Craig (Ben Addis) was killed. Everyone was keeping a secret – and Caleb’s was that he and Tracy had shared an illicit kiss. And then another one.

Caleb’s jealousy levels are tested (Picture: ITV)

‘It was a bit of a shock but it feels totally motivated to me,’ William Ash said. ‘All the building blocks were there, albeit very subtle I feel like they were there.’

Since then we’ve seen them obviously lusting after each other but trying to keep their passions at bay. In upcoming episodes we’ll see them again giving in to their attraction to each other.

The actor said that, for Caleb, the fact that the liaison is all kinds of wrong due to Tracy being married to Caleb’s nephew Nate (Jurell Carter) is the reason why it’s exciting for Caleb.

Caleb seemingly forgets the meaning of family loyalty (Picture: ITV)

‘Caleb’s motivated a lot of the time by just wanting everything,’ he explained. ‘If he knows it’s taboo and he knows it’s forbidden, he’ll go after it anyway.

‘He knows he shouldn’t be sleeping with his nephew’s wife, but because he knows he shouldn’t do that, that’s what he wants to do.’

Of course the affair threatens to not only blow apart Tracy and Nate’s marriage – which is only six months old – but also destroy the rapport Caleb has recently built with his brother Cain (Jeff Hordley), who is Nate’s dad.

‘He does like Nate, he’s not trying to get one over on him in that sense’ Will insisted.

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‘He is being really snide because it’s pretty abhorrent what he’s doing. I think he does wrestle with that a little bit. He wrestles with that quite a lot, the fact that he is being pretty despicable towards his nephew.’

‘Also the cost of it, that it could possibly blow up his relationship with Cain. That’s not gone under the radar with Caleb. He’s not blind to that. He knows it’s a really, really dangerous game he’s playing. But he can’t help himself.’

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Caleb’s landed in more trouble.