Doctor Who spin-off The Sarah Jane Adventures is now in its fourth season and is one of the most popular CBBC programmes. Its star, ELISABETH SLADEN, 62, has been playing the intrepid journalist on and off since 1974.

She discusses working with Doctor Who star Matt Smith, and Katy Manning, who plays fellow former companion Jo Grant.

Are you surprised by the success of the Sarah Jane Adventures?

I WAS early on, but not now, when you can see what we can do and the format, how it works.

It’s a quality programme, not a cheap one. It’s expensive by children’s standards.

Julian Bleach was very frightening in the first two-parter.

I know he was very scary during filming too.

You’ve worked with him before – didn’t he play Davros in Doctor Who?

He did indeed. Our director, Joss Agnew, did a fantastic job this year. We were doing one scene and he said, ‘Lis, can you do it a different way, just in case we need it?’ Because although all ages watch the programme, you have to be aware of the audience you’re actually making it for. So we were being careful because it was a scary one.

The big surprise was that Luke K-9 left at the end of the first story.

It makes a very good story and it’s right that they move on. Also, it’s kind of like what the children watching will do, what they might be planning.

Tommy (Knight, who plays Luke) found it difficult last year because of the filming schedule and his exams, and we didn’t want that again. So this year, when Luke goes off to university, Tommy’s actually doing his exams.

Would you like your own K-9 in real life?

Not really. The thing is, he could be very useful, but he’s quite a large, immobile object and I just don’t have room for him.

The big storyline this year involves the Doctor and Katy Manning’s return as Jo Grant, another former Tardis traveller.

I know. It was great fun. I knew Katy socially, but I’d never worked with her before. And there’s no mistaking Jo. In her own sweet way she’s just as bonkers as she’s always been.

Matt Smith says he had a great time filming the show.

Oh bless his cotton socks. I think he’s gorgeous, and we absolutely adored having him there, as you can imagine. It was nice for him to just enjoy it, without the stress of carrying the whole show.

Do you get pestered in the street by fans?

No. I get recognised, but I never get bothered.

They’re lovely, young or old. I have to say it generates nice fans, who are always very polite and pleasant. They make me laugh as well.

Do you see any of your old friends?

Now and again. I saw Tom (Baker) in February this year, I spoke to Nick (Nicholas Courtney, who played the Brigadier) on the phone. But, of course dear Jon (Pertwee) is no longer with us. I spoke to Terrance Dicks recently, who was our script editor.

And I used to keep in touch with Barry Letts, our producer, but sadly he’s no longer with us either.

Terry and Barry were responsible for Sarah Jane and, in a way, for me as well.

Is there anyone you’d like to have guest star in the show?

Oh loads of people. I did at one point want Meat Loaf, but I don’t think the budget would stretch. I do think he’s gorgeous though. I love the TV show Monk, too. Tony Shalhoub is brilliant, but I’d prefer it if Stottlemeyer, played by Ted Levine, turned up as a detective in Sarah Jane.

How do you keep in such good shape?

Drugs of course. No, not really – running up and down those attic steps. And chasing after a bunch of teenagers on set. There’s never a dull moment.

Have you got any more projects planned?

Oh God no. I’m still working on Sarah Jane. And I’m co-writing my autobiography. I was supposed to be going on holiday, but I haven’t been able to find the time yet. But I’m looking forward to Christmas, it’s my favourite time of year.