Doctors: The joy (and pain) of creating characters
This has happened before and it will happen again, but as series producer, one can't help feeling frustrated at creating a successful character, only to have him snatched away from you because the artist concerned is keen to do other things with his career.
Shouldn't be allowed.
Of course this is completely unfair. David is a talented young actor and has a lot of things he wants to do, we were probably lucky to have him for as long as we did and we got to tell some great stories with him.
Still - damn!
But life, and the Mill, goes on and eventually we all have to come to terms with such departures and try to see the huge gaping hole of their passing as some kind of opportunity.
Ironically, it's some six months later when we get to see the audience's reaction to a character's exit, and how annoyed they get - "Now George and Ronnie have left, I refuse to watch it any more" and "It's just not as good without Vivien".
Alright already! I know I know, but it's not my fault and much as I'd love to, I just don't have that kind of power over actors' lives and ambitions.
I truly wish I did, but sadly it's beyond my job description and I'd probably get fired if I tried.
So you learn to see this as an opportunity, a chance to refresh the cast and introduce some new faces to stir things up.
The editorial team always start with the characters we have already, draw a kind of map and then look at the types of characters we don't have.
Characters don't just leap up, fully formed. If you're not careful you end up putting all kinds of ticks and tricks into a biography to make them interesting... 'supports the Villa', 'collects china pigs'... and it ends up like Top Trumps.
And the next time someone says 'has a dry sense of humour' in a story meeting, I'm going to make them leave the room and stick their head in a bucket.
Everyone likes to think they have a dry sense of humour!
There are all kinds of ways to create characters, there's a whole industry (based in Hollywood naturally) that's dedicated to systems and archetypes and templates for dramatic characters.
Great writers don't need them. In fact many top writers find them stultifying and needless.
But these are very talented men and women and stuff like this comes naturally to them. Then there's the rest of us...
In story meetings the editorial team often talk about people they've met/are related to who may provide inspiration for new regular characters.
Always interesting as examples of behaviour, but you'd never do a direct lift. Real people are never very useful dramatically.
They're less consistent and more chaotic than fictional characters - and the audience likes to know where they are with someone they're supposed to love/hate/sympathise with.
Of course our characters can be chaotic and inconsistent, but the audience likes to be in on the secret of why they are behaving like that.
Unless you know a person really well, you never have that kind of intimacy, and intimacy is the key to series drama.
If you've created your characters well, then the audience will be able to anticipate how their favourites are going to behave.
Of course sometimes you can subvert that and have even more fun with it.
But you need to know what your characters' flaws and strengths are. The writers have got to put them into all kinds of situations and they need to know what makes them tick and how to write them.
If I've got a good sense of a character's 'voice', I will write some sample scenes to give writers a clue and use at auditions.
Some writers really struggle to get these voices right. They may be more interested in plotting than they are in characters.
Or they may be brilliant at writing their own characters but less interested in writing someone else's.
But if you're going to write for series drama, you're going to have to get the knack of it, or you'll be rewritten somewhere down the line... and you probably won't be asked back.
So, after all this mapping and ticking and strategising and matching and mismatching, you produce a biography that hopefully makes things clear to the writers and the make up artists and the costume designers.
You've thought about what kind of car they'd drive for the art department, and you've supplied enough of a physical description to give the casting directors some idea of what you're looking for, but you're not so prescriptive that they laugh you out of the audition room.
But after all this, it comes down to casting the right actor. Cos however much prep work you do, if you pick the wrong actor, or worse, a bad actor, then you're screwed and all your hard work comes to nought.
But we got it right with David Sturzaker and with Lu Corfield and Simon Rivers, I think we've got a couple of corkers.
So farewell Simon, and a great big welcome to Dr Kevin Tyler and Dr Freya Wilson!
Peter Lloyd is currently the series producer on Doctors. He has also worked as the script editor, producer and series editor on the show.
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Comments made by writers on the BBC TV blog are their own opinions and not necessarily those of the BBC.