Una Stubbs, Sheila Reid and Susie Blake talk about playing the coach trip trio of Peggy, Mildred and Marge.

What drew you to Murder On The Blackpool Express?

Una: The funniness of the script and also Johnny Vegas was a big draw for me.

Sheila: Yes, we both worked with him before in Benidorm and he is completely adorable, one of the nicest men in the entire world. So it's a great treat to work with him again. And like Una, I think the script is fantastic. It's gloriously written and a great joy.

Susie: I had no idea until we did the table read who was in it, to be honest. But I arrived and I saw everybody I've loved and admired and wanted to work with forever, so it was no question for me. It's a fantastic cast.

Can you describe your characters please?

Sheila: Mildred is a woman of surprises. She has travelled the world and had a lot of experience. She's a very gentle, loving soul at heart. Very warm and caring but emotional. Not terribly clear in her thoughts. Tends to be what one might term 'dizzy', or a bit of a firefly. She's great fun to play. She wants reality but she finds it hard to base herself in the centre of the real world.

Una: Peggy's quite stoic really, and sometimes irritated by Mildred who weeps regularly. But on the whole, basically quite a nice woman.

Susie: Marge is a grumpy old cow! She's got a sense of humour that comes across as aggressively unpleasant but it makes her laugh that she's so beastly to other people.

Why have Mildred and Peggy come on a trip with Marge?

Sheila: The trip was her idea and we were too scared to say no!

Susie: She's lucky to have two such loyal pals because she's not a nice person. I'm sure she had a very terrible life.

Is it nice to work so closely together?

Sheila: It's absolutely terrible, can you imagine? No, it's obviously lovely, and it's wonderful having that group dynamic to work with. We've sat and talked about our back stories and what our characters have done in the past.

Una: I think it's tedious when actors always say, 'Oh we're such a happily little family', but I'm afraid we are. I think it comes from the top and Johnny just spreads that. Such a good gatherer of people that makes a lovely friendly atmosphere.

Is it a whodunnit or a comedy or a pastiche?

Una: It's like a comic drama.

Susie: Yes, definitely. There's lots of drama to it and it's funny.

Sheila: It's a riveting story. It's really interesting to see what's going to happen.

Una: And you don't know until the end whodunnit. There are very good red herrings.

Susie: I don't think there's anything in it that's going to compete with the very dark detective series that we've become used to, because it's more about the characters than who kills who. It's actually more interesting, in a way. And it's not heavy.

Sheila: And the fact that the two main characters, Terry and Gemma, are such innocents really. And suddenly they are plunged into this terrible world. They are our anchors.

Have you been corpsing much, as it is so funny?

Una: The thing is, when you're ready to say your lines, there's a sort of tension. So if it goes wrong, it releases a spurt of laughter very quickly. We did do this the other day and it was not fair at all on the poor person who was facing us.

We had our back to the camera so it didn't matter that we were laughing but the poor person facing us had to
try and keep a straight face. I won't say who!

It was my fault. I had a line that I got the wrong way round. It's not so much that you find it funny, but because you're quite taut and you're concentrating so when you hear something ridiculous, it is like an elastic band losing its tautness - it pings off.

What do you get up to in between scenes?

Susie: Well, I brought my hobby along. Una is an artist so I brought my sketch book along because I want her to help me. And Una always has a sketch book with her. She is brilliant. She has a portrait of Bill Nighy in the National Portrait Gallery.