The actress co-created the original drama in the 1970s with fellow actress Jean Marsh, and when it made a comeback on U.K. TV in 2010 she wanted her character, Maud, Lady Holland, to have an exotic pet.
But producers were so against the idea they stalled filming scenes featuring the monkey, named Solomon, and tried to convince the actress he was too expensive to have hanging around on set.
Atkins tells U.K. newspaper the Daily Mail, "Heidi Thomas, the series writer, didn't like the monkey, nor did the producers. But I thought the show needed livening up and Solomon was brilliant.
"One day... I knew they didn't want the monkey in the scene but I thought it was necessary. The monkey was hired for the day but they kept delaying the scene. I could see what they were doing; it was so f**king obvious that they were hoping to run out of time so the monkey couldn't be used.
"I said to the producer that if we got to the end of the day and we hadn't done the scene with the monkey, I would want to do it tomorrow. First, they tried to tell me the monkey was too expensive to hire for another day. So I asked them how much Solomon cost. They said £2,000 a day, so I wrote them a cheque for £2,000. Then they told me that the monkey wasn't available.
"I can't stand it when people lie to me. If Heidi had said right at the beginning she hated the monkey, then I would have chosen another pet - a parrot maybe - instead. I hit the side of my trailer and I said: 'If you don't get the f**king monkey, then you won't f**king have me'."