Who managed to be a Dalek for the day?

She climbed in, put on the helmet, and darted around the studio for a bit of fun. And did she use the immortal words? (Exterminate! Exterminate! in the unlikely event you've never seen the show).

"Probably. I'm sure we all did. I think everybody was fascinated," she says.

We are taking a journey back in time to the early 1960s when this young Shrewsbury woman was hand picked for the small BBC team working on a new show called Doctor Who which would take British television into a whole new dimension and create sci-fi history.

"It was a bit of an honour, I suppose. I was probably picked because I was fairly competent, or maybe I was just free," said Catherine, who is now 74 and lives in Pontesbury, and had worked at theatres at Bristol and Coventry before joining the BBC just after her 21st birthday.

The idea was for a pilot show featuring a time traveller in a machine called the Tardis (standing for Time and Relative Dimension in Space).

Catherine Childs, as she was then, worked for the BBC television drama department. The full Doctor Who team was, she says, Waris Hussein, with Douglas Camfield as his assistant, and Catherine as Douglas' assistant, with a secretary making up the fourth place.

"I read the script, but I can't say I was bowled over. I don't think anybody was, particularly. I thought it was an interesting idea," recalled Catherine, the assistant floor manager, who was plucked from a soap called Compact to work on the new project.

"I think we were recording that first episode in about November 1963. We did outside filming in a scrapyard somewhere in London at night which was very cold and pretty grubby, which was where the Tardis landed for its first arrival."

Rehearsals were done in a drill hall at Hammersmith or somewhere like that.

Playing the part of The Doctor was William Hartnell.

Catherine said: "He had been in the Army Game and was well known. The scriptwriters and producers thought he fitted the profile of what they wanted The Doctor to be, as indeed he did."

Reaction to the new show was fast and positive.

"It was transmitted on the Saturday in the 5 or 6 o'clock time slot. I remember coming in to the office on Monday. We were waiting in some trepidation. Then news came through that the powers-that-be liked it and the viewing figures were good. So very quickly they said right, we're going ahead with the next four episodes."

These involved the Tardis going back in time to the Stone Age. "That involved some night filming in some ghastly old claypits, somewhere on the outside of London, an extremely muddy place to do some caveman stuff. It was cold because it was winter."

Meanwhile another team was working on the four follow-on episodes which were to introduce the Daleks, one of British television's most terrifying creations, viewed by a generation of children from behind the sofa.

And although Catherine was not working on those episodes at the time, she did have the chance to have a personal encounter.

"I remember being in the studio recording when the Daleks were very much around. I remember sitting in a Dalek and propelling myself around the studio floor in it. You sat on a board inside this shell with your feet on the floor. It had four casters.

"The top of the Dalek came up and the actor climbed in, and the helmet was put on top. There were eyeholes and a stick you moved around – a plunger with a ping pong ball at the end. The whole thing was sprayed silver. I had a bit of fun. It must have been in a lunch break."

But it was not these monsters that caused Catherine as much grief as The Doctor – the tetchy William Hartnell.

"He was something like 67 when he did this and found it increasingly difficult to remember his lines. He was ageing and probably becoming a little insecure. He was not the easiest actor to work with. I was probably the first in line for his irritation.

"I could never get it right. I would prompt him, and he would say 'No, I don't want to be prompted,' or I would not prompt him, and he would say 'Why have you not prompted me, girl?'."

Catherine dealt with it professionally by taking no notice of his irritation. In contrast, William Russell, another of the early cast, was a delight and "could not have been an easier or nicer man to work with."

Having been in at the start meant Catherine was one of the first to hear the innovative theme music.

"That involved the BBC Radiophonic Workshop. Ron Grainer was the composer for the opening sound effect – bom di bom, bom di bom – which was the first synthetic music titles. I remember we went to hear that before it was agreed. I had never heard music of that sort." She remembers being in the radiophonic workshop and people were asked what they thought.

"We were all utterly intrigued. Would it make a good bit of title music? It did, didn't it, and the rest is history, as they say."

Catherine went on to work on classic serials for the BBC, and then on to the first Forsyte Saga, with its star-studded cast of Eric Porter, Nyree Dawn Porter, Kenneth More, and Susan Hampshire.

"I enjoyed it tremendously. It was extremely rewarding, with a much bigger cast and some phenomenally good actors."