The 79-year-old Harry Potter star admitted she felt "frightened to go the theatre" and is eager to be vaccinated.
Margolyes told The Guardian: "They’re absolute nitwits! I’ve never been governed by such a crowd of corrupt incompetents in my life. I’m absolutely furious about it.
"And this whole Brexit thing is affecting our business, too. Musicians are not able to get jobs in Europe. It’s catastrophic. I want to grow old feeling optimistic and grateful, but it’s not happening. I am growing older, angry and disappointed. I’m getting further and further to the left. Usually, when you get older, you go further to the right."
The actor and TV presenter – who revealed she is currently in Italy – was in coversation with Call The Midwife narrator Vanessa Redgrave, 84, who revealed she has had her first dose of the coronavirus vaccine.
Margolyes said of the pandemic: "We’ve forgotten how to be an audience. We’re all at home, streaming movies... Will it be safe for people to be in the same room with other people?"
She added: "I’m frightened to go to the theatre. Other people have become the danger. You get the virus from other people. Have you had the vaccine?"
Last month Margolyes called prime minister Boris Johnson a "clown" as said she would not be returning to England “until it’s safe to go”.
She told Good Morning Britain: “I mean, you’ve got that clown in charge there that I didn’t vote for and I’m holding him responsible for a lot of this mess."
It wasn’t the first time that Margolyes has lashed out at Johnson.
Last year she caused a stir following an appearance on Channel 4’s The Last Leg when she admitted she “had difficulty not wanting Boris Johnson to die” after learning he had COVID-19.
The comments prompted shocked responses from the show’s hosts but Margolyes quickly went on to say that, despite her initial thoughts, she didn’t want to be “the sort of person that wants people to die” and really did want him to get better.
The prime minister was diagnosed with the coronavirus early in the pandemic.
Watch: Miriam Margolyes said she hoped Boris Johnson would die from COVID-19