Simon MacCorkindale tells Graham Kibble-White why he likes parts to come with a cause...
As part of the BBC's DoNation season, Holby City and Casualty join forces for a special interactive episode in which viewers can vote to determine the outcome of an organ donation storyline.
Central to the process will be Casualty's director of emergency medicine Harry Harper, who'll reveal the decision at the end of the show.
For actor Simon MacCorkindale, the hospital drama's passion for tackling important issues has always been central to its appeal even if, as he admits, its focus has changed from its early years.
"I remember the first shows," he says, "which were much more politically based. But these were the days when the BBC and other programme-makers were perhaps a little bit more erudite than they are now.
"We still try and tackle issues, although the demand nowadays for fast-paced action makes didactic arguments a little harder to deal with.
"My character gets involved with these things quite a lot because he's not only a doctor, he also does a lot of clerical work and he's the head of the department. That means he has an opinion about waiting lists and all that kind of stuff."
Asked what prompted him to join the cast of Holby's finest three years ago, Simon smilingly reveals: "Well, first of all, they asked me if I'd like to be in it."
He continues: "I had been looking to get back into something substantial in the UK, having travelled a lot, but I hadn't really decided what sort of thing it would be.
"When they presented Harry to me I thought he was a great creation and a new type of character for the show. The producers told me that they just wanted to up things a notch, go back after the ratings and try and push them up again.
"Once they decided they would use me instead of someone ten years younger, we went down the road of saying, 'Let's put the centre back into the programme in terms of the discipline'.
"Hence Harry arrived wearing a smart suit and looking much more like an old-fashioned consultant rather than a young doctor trying to be on the pages of GQ.
"I think it's worked well for the show. It's sort of grounded it and put the centre of the wheel back."
Aside from bringing a steadying influence to proceedings, 53-year-old Simon has also relished the chance of grappling with the complicated jargon the show often employs.
"That side of it is very demanding," he reveals, "and I have made it my challenge to be as convincing as possible with all the terminology. So when the script-writers come up with medical expressions I want more, not less. I want to stretch myself by trying to remember them, understand them and deliver them in a way the audience believe I know what I'm talking about."
It's all a far cry from working on the US glamour soap Falcon Crest, where Simon spent two years in the mid 1980s.
"That was an out-and-out soap opera with precious little additional value," he chuckles.
"It was a different time in my life. I was in America making good money and getting quite a decent profile, but at the same time I was rather arch about the work and had that bit of Englishness about me, you know, 'I don't know that I should really be doing soap opera'.
"I'm not sure I would have said to my chums, 'Stay home on Friday night and watch me in Falcon Crest'. I'd have been more likely to tell them, 'Look, I'm sure you've got something better to do with your evening'.
"I'm enjoying Casualty way more than I did that show. I find it a very complete, rewarding experience whereas Falcon Crest was on the edge of stupidity a lot of the time."
Talking about the edge of stupidity, Simon then casts his mind back to recall his time in the short-lived adventure serial, Manimal, which told the tale of a crime-fighter who could transform himself into any animal.
"I have to say, I thought the original concept of the programme had real potential," he says. "If you think about it, this was the early 1980s, before Kyoto, and before everyone was getting into green issues. We were dealing with all those sorts of notions, but, unfortunately, as it was Hollywood what we actually ended up with was a cop show in disguise.
"However, having said that, if you look at the episodes we did, we had two or three that really broke out from that mould, and when they did I thought the series really began to take off.
"Sadly they canned the show because we went up against Dallas on a Friday night, and it killed us stone dead.
"It's become something of a cult around the world, though, and I get as much mail for Manimal as I do for anything else. In fact, when I first joined Casualty, all the young actors were saying, 'Oh my God, I can't believe it's Manimal!'."
For those who'd assume a serious thespian like Simon would rather forget about his shape-changing salad days, it's a surprise to hear him say: "I thought it was a really cool concept. Actually, I would love to see it come back.
"If it did, I'd play it in a different kind of way, but yeah, absolutely, I'd do it."
Until then, there's more immediate matters to think about, including just what the new series of Casualty - which kicks off on Saturday September 10 - has in store for Harry.
"He's down on his luck as far as girls are concerned," says Simon, joking. "He got turned down by Lara and Selena so he's going to become a serial killer.
"No, seriously, he is actually going to have a relationship, so we'll be seeing a bit more of his lighter side.
"To be honest, I don't know an enormous amount about what's going to be happening, because I like to be surprised by what the writers throw up. That becomes part of the challenge, as you go, 'Oh my God, is that the story they're doing? How am I going to tackle that one?'."
* Casualty/Holby City Special - Something We Can Do is on BBC One on Saturday August 27.