Heartbeat star Joe McFadden joins the cast of Casualty this autumn as Polly’s stalker Alistair. We spoke to Joe about his new role…

How did you get involved with Casualty?
“They knew me from a couple of years back when I played the part of a guy who was on a stag night and falls down this manhole cover. He ends up nearly drowning and getting his hand chopped off – the usual gruesome stuff they have in Casualty. I’d had such an unpleasant time in a water tank for three days that they rewarded me for not moaning too much by giving me this character a couple of years later!”

Tell us about your character Alistair…
“The good thing about being in the first couple of episodes is they always pull out all the stops and it’s very dramatic – they blow up a shopping centre. Alistair is a homeless guy who lives in the cardboard city that’s underneath the shopping centre so the paramedics are called out and I help them evacuate the place and become quite friendly with Polly. We become quite firm friends quite quickly.”

But then he gets obsessed with her, doesn’t he?
“Yes, he is a bit damaged from living on the streets – he obsesses about Polly more than he should do and reads more into their relationship than he should do. He’s got mental health issues as well.”

And then things start to take a sinister turn…
“Yeah, he stalks her a bit, places all his happiness on her shoulders and obsesses about her. He ultimately becomes violent and lashes out at her. In his mind they’re having a love affair but she’s just being nice. She’s this lovely, open, friendly girl and he just reads too much into it. When she rejects him he doesn’t take it well!”

What was it like having to dress down to play a homeless person?
“It was lovely after two hours of having to shave every morning on Heartbeat and being brushed down and not being able to eat in costume it was really, really nice just to be able to slob around not shave and sit on the ground if you wanted to and get mucky!”

Did any funny incidents happen on set?
“I was getting arrested one day for an episode and we filmed it on a little camera. You couldn’t really see that we were filming and I was being taken away by these two policemen and was resisting arrest. Then this police car comes out of nowhere and I was almost arrested for real, which was really funny. Also, in the beginning when I’m sitting around begging in the street and asking for money, people were actually giving me money – I made a few quid!”