Doctor Who star says William Hartnell was "furious" over cast changes

"I was heartbroken when she left," Purves said of O'Brien. "We got the new scripts for [1965 serial] The Myth Makers – sadly of which nothing remains – and Maureen read that in episode 4 she left the show. She didn't know. She found it in the script. It was a shock – it was a shock to Bill [Hartnell]."

Purves – who was speaking at a BFI event to mark the release of the Doctor Who: The Collection - Season 2 Blu-Ray boxset – recalled Hartnell being "absolutely furious" at the news of O'Brien's departure.

"The sad thing was that she was never really replaced – because she was replaced by Adrienne Hill from The Myth Makers [playing handmaid Katarina] for five episodes. We all thought she was the permanent new girl, but it was decided that a girl coming from ancient Troy could not cope with the science elements of the show and wouldn't understand all that, so after five episodes, they just junked her, literally."

Katarina became the first Doctor Who companion to be killed off when she perished midway through The Daleks' Master Plan, with Jean Marsh fulfilling the companion role for the remainder of that story as space security officer Sara Kingdom.

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"Jean Marsh was established then in the programme for eight weeks, which was all she could do – she was never going to stay longer than that," Purves explained. "So the cast kept on changing, which was not the nicest environment to work in, and didn't make any of us feel particularly secure.

"I never felt secure in the job – once Maureen had gone, I thought I could go at any time."

He continued: "I discovered later that I wasn't in jeopardy at that time, but Bill was, for a variety of reasons. They kept on trying to find ways of writing him out of the show."

Purves pointed to two stories, 1966's The Massacre and The Celestial Toymaker, in which the Doctor plays a smaller part in the narrative as evidence that the production team were trying to "find a way of seeing if the show worked with Bill having much less of a role".

Looking back on his time spent working with Hartnell, Purves claimed that the actor would sometimes struggle to remember his lines, delaying production, but insisted that they worked well together on a personal level.

"Bill had loads of faults. Don't we all? But for me [...] he was a lovely man to work with, and when you knew him, you could make all sorts of allowances for his really serious faults and you could help him through the difficult times he was having.

"We stood around on many occasions, whilst we were recording, waiting for Bill to get back on the script. We knew we'd get there, eventually.

"We might even be able to give a hint line – just a word or a nudge or something that would put him back on track. So I mean, he wasn't easy to work with in that respect, but he was a joy to work because he was such a nice man. I liked him a lot."

Doctor Who: The Collection – Season 2 is available to pre-order now from Amazon.

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