Jan Ravens was in the Cambridge Footlights when Imogen Stubbs was testing her mettle in the Oxford Revue. Both highly successful in their own right, these two went head to head at the Edinburgh Fringe Festival back in their day. And now both are appearing at the Oxford Playhouse this week. We find out what, if anything, has changed since their university days.

“THE Oxford lot were so much more glamorous than us,” Jan Ravens remembers, “and Imogen Stubbs (see opposite page), she was so gorgeous and intelligent.

“It’s funny how you always want what you haven’t got, isn’t it?” she adds.

Which is ironic, considering that famous impressionist Jan Ravens was President of the Footlights when Emma Thompson, Hugh Laurie and Stephen Fry were all aspiring comedy stars.

But Jan says that as she was studying teaching at Homerton College, she wasn’t a real bona fide Cambridge student and therefore didn’t quite fit in.

“I was quite in awe of them all because I was from middle-class suburbia, and felt a bit like a fish out of water.

“So I didn’t feel part of a big glamorous set, I just kept thinking they’d find out and that would be the end of it,” she admits.

“Because as soon as Emma Thompson walked into the room you knew she was going to be a star.

“She had this aura of confidence and self-possession, and Stephen Fry and Hugh Laurie were a phenomenon even then, and it was pretty obvious they were going places.”

What Jan fails to mention is that she was also going places, and still is, most notably the Oxford Playhouse tonight, where she is doing a deconstruction of the impressions that have made her a name on programmes like Dead Ringers, Alistair McGowan’s Big Impressions and Spitting Image. In fact, since she graduated, Jan Ravens has scarcely been off our TV screens either as an actor or an impressionist.

But the mum-of-three still thinks it’s terribly important to keep doing the live shows, see what people actually want to laugh at, and what they are interested in.

“You can get very self-indulgent in a studio, although Dead Ringers always has a live audience.

“But it’s important to get out there because in the end that’s what it’s all about – getting in with the audience. And in London, people get a bit blase about comedy.”

Jan obviously loves doing her show A Funny Look At Impressions.

“It’s almost my story and the story of impressionism. It’s like a little tour and I teach the audience to do impressions themselves.

“I feel very ambivalent towards costumes and make-up, because while I love all the dressing-up, I think it can spoil the effect, because people might be thinking I don’t look enough like someone, even if I sound just like them.”

And to demonstrate her point, she slips effortlessly into her Sharon Osborne impersonation, almost chilling in its accuracy.

So does Jan have to concentrate hard to copy her characters, or does it happen naturally?

“If you are a natural mimic, you have that in you and some characters will just slip out, as if you have a particular chip that enables you to see and hear what’s going on and reproduce it.

“But other characters are much harder and you have to listen and look at their physical idiosyncrasies, almost like a cartoonist, and find the key to that person, until people say ‘that’s it, that’s it, that’s what they do’ without actually noticing what they do. So it’s a physical and mental challenge in all sorts of ways.”

MPs like Hazel Blears must be a gift, then? “Yes, except I have to rewrite the script every day at the moment,” Jan laughs.

And where does Jan draw the line between being spot-on and too personal?

“I try not to be unreasonably cruel,” she says, “but sometimes I have to take personal appearance into account because otherwise the character won’t work – like Cherie Blair’s mouth.”

Now that Jan is on tour and on TV, maybe she will finally give herself a break and admit that she’s made it: “I never imagined that my life would be like this because it’s so different to the life my parents lived. It’s another world.

“This was always an unknown quantity to my parents, because we had no theatrical background at all and it was out of their own experience,” she says.

So did that make her more determined?

“Yes, because I had to find a way around that, but that was the thing about Cambridge, people were much more confident, and posher than me, and it gave me a window into that world that made it all seem possible.

“Because people weren’t afraid to be individuals or a bit different, which was quite liberating. And I never did use that teaching degree ...”

Jan Ravens brings A Funny Look At Impressions to the Oxford Playhouse tonight. Box office on 01865 305305.