Comedy acting legend Frances de la Tour is back for a second series of Big School...

Are you glad to be back filming Big School once again?

I am extremely glad to be back. I loved watching the first series and I think a lot of young people liked it first time round too, which is really nice.

It is very interesting when you make a show like this as sometimes it takes more than one series for people to get to know who the characters are but I think with Big School they are all instantly recognisable.

For those that might have missed the first series, how would you describe Ms Baron?

Ms Baron is the headmistress of Greybridge School and I would say she is authoritative, naughty, outrageous and despicable. She would be very happy to smoke a joint or drink a bottle of wine whilst in her office. Ms Baron isn't depressed but she is reckless and she gets pissed off. I don't think she drinks out of depression but I do think she is naughty. That's the main word I would use to describe her.

Do you enjoy playing Ms Baron?

Ms Baron is the most outrageous woman I have ever played. I definitely enjoy playing her and I am pleased we are back and hopefully Big School will become an ongoing thing so we will see much more of her. Very often you have to say goodbye to a character very quickly but this has become more of a theatre piece which I am used to and enjoy a lot.

You live with a part for a while and this way if you do it once a year you can have a good stab at it.

It would be fair to say that everyone at the school, teachers included, live in fear of Ms Baron due to her no-nonsense approach, but do you think there is anything that scares her?

It is revealed in this series that the school could be closed down because it is so awful. I think it is the only time we see Ms Baron being nervous. If the school were to go then her livelihood would go too and that is what makes her concerned about the OFSTED visit that happens in episode four.

Everybody in that staff room needs each other so it's an interesting concept. They are much more dependent on each other than anyone would want to admit, that is what is so interesting about this show.

The school is a bit like The Italian Job in that respect, as everybody is in on it. If the rest of the staff at the school were not in on it they would lose their jobs and if that happened they wouldn't be employed anywhere else because they are all so terrible as none of them can actually teach very well!

Do you think that Ms Baron has any favourite teachers? Or does she have equal distain for all of them?

I think she has a soft spot for the most vulnerable which would definitely have to be Mr Barber - he is such a lost soul.

How was it filming in a real school?

We were really amazed with the children we worked with in the school; they were so on it and with it. I had some pretty ferocious assembly scenes to film and had to say some foul things in front of them.

Is it difficult to deliver some of Ms Baron's very amusing lines in such a dead-pan manner?

The only way I can get through the series is to stay completely straight faced otherwise I couldn't get through the scenes. What Ms Baron says is shocking and you don't expect her to say some of the outrageous things she does, and that is what is so clever about the writing - you just expect her to be another harridan but then she will suddenly come out with these outrageous comments. Who knows if she could be drunk or high on drugs half the time, but it is funny and it is a lovely idea and yet somehow she manages to retain her authority.

Like all comedies, we as actors are all playing characters. But what prevents us from all turning into caricatures is that we are stopped from going off-field by the brilliant scripts written by David Walliams and the Dawson Brothers.

There are lots of great guest stars joining the series. Without giving too much away do you have any memorable or favourite scenes with any of them we should look out for?

I do love working with Sylvestra Le Touzel because she comes in to play another harridan. It is quite interesting because she is playing my counterpart and she is somebody in real authority rather than Ms Baron. Although Ms Baron can expel any student or sack any teacher she doesn't have authority with the local council as they come checking up on her and that is when we meet the School Inspector Ms Steele played by Sylvestra. It was lovely working with her as I have known her for quite some time and it is always nice to see a friendly face.

I think the regular cast are smashing too - in my opinion Big School is beautifully cast. I think all of the actors involved are a very good match for their characters and I hope everyone enjoys watching it.

Deep down, do you think Ms Baron cares about the school, teachers and children?

Even with comedy you have to apply the same questions as you would to drama in terms of truth. I think somewhere she cares very much if only for herself because what would her life be without the school? I think she would be very concerned about retiring, because her life has been full of this naughtiness and exploitation at the school. If she were to ever leave, I don't know whether someone like that would find what she has there elsewhere. Even if Ms Baron were to volunteer and end up being the harridan of a local Bridge Club, I think no matter what she did she would always be a very naughty, outrageous and atrocious woman. Does she care about the children? She probably does in a funny way.

And finally, has Ms Baron learnt Miss Postern's name yet?

I think she completely knows what her name is but she finds Miss Postern deeply, deeply irritating - but she also know that she needs Miss Postern too.