“In the 1970s, you couldn’t rehearse at the National after lunch because everyone had drunk too much!”

June Watson was born in Edinburgh in 1935 and has had a 67-year career on stage, television and film. Although she is best known for series such as Accident, The doctor and the dear animals And Agatha RaisinThe theatre is her great love and over the last decade she has given a number of unforgettable performances, most notably as Mammy in Michael Grandage’s production of The Cripple of Inishmaan (for which she received the Clarence Derwent Award), as the mysterious Genevieve in Annie Baker’s Johndirected by James Macdonald, and most recently as old servant Firs in The Cherry Orchard at the Donmar Warehouse. She has been married to actor and director Christopher Dunham since 1962. Next month she will star alongside Mark Strong and Lesley Manville in Robert Icke’s new modern Oedipus.

What role do you play in Oedipus?
His mother Merope. She is only mentioned in Sophocles’ play, but Robert [Icke] decided to make her a character who actually appears. He has a reason! It’s not an adaptation of the original. It’s his version of the Oedipus story, really powerful. And a great cast. I absolutely love it.

You are currently experiencing the peak of your career and are working with all the top directors.
I know! I am a very lucky woman. I have done about 25 productions at the National and many with the Royal Court. I had a wonderful time as a founding member of the English Shakespeare Company and travelled around the world. But suddenly in 2016 I saw Caryl Churchill’s Escape alone at the Royal Court, directed by James Macdonald. And that kind of re-energised me. If you’re looking for an old lady in a play, that’s usually me.

Why do you think this is so?
I guess it’s because I can still learn the lines. I think people my age either can’t learn it or think they can’t and panic. I can’t see very well. I have macular degeneration like the great Judi Dench, but as my eyesight started to fail, my concentration got better. Of course, my husband has to help me learn. I can’t see the script in print, so I have to learn it before rehearsals start.

Dame Judi has given up stage acting because of her eyesight. Do you need any special concessions?
When I have to go up and down stairs, I need little neon lights so I know where the first step is. But when it’s flat, it’s not complicated, I can see. My peripheral vision isn’t that bad yet. I manage and just force myself to do it. I don’t give up.

How did you get into acting? first of all?
It was my mother’s fault. She was a working-class girl who wanted her children to have a hobby, so we all had to go to piano lessons. At one point the teacher said, ‘Mrs Watson, you are wasting my time and your money because June has no talent for the piano.’ Then she spotted an advert for acting lessons and asked if I wanted to do it. And I said no. I only wanted to date boys. Anyway, she persuaded me to go and I was absolutely delighted. I was about 12 years old. At some point I plucked up the courage and asked my father, who was a fishmonger, if I could go to drama school. He said yes, as long as I didn’t leave home. It had to be in Edinburgh. That’s how I started.

When was the point where you felt like you had arrived?
Peter Gill was the first director who was really interested in me. [In 1976]he wrote a play entitled Small change and there were two wonderful roles for women, played by myself and Marjorie Yates. Everyone wanted to work at the Royal Court and that gave me a career in London. But I was always a supporting actress. When I was a young actress and started in repertory, I played the “character roles” – I was everyone’s mother or aunt or even grandmother. I never rose above the title.

Is there an advantage to this?
There is a lot of pressure when you have to carry plays. I don’t have that pressure. It’s nice to just perform for four or five scenes and do your bit and then have a cup of tea. Maybe I would have liked to do a bit more – I would have liked to play Lady Macbeth – but I’ve had a very good career.

You were part of the famous Bill Bryden The company at the National Theatre in the 1970s, when they From Lark Rise to Candleford And The Passion. How was that?
It was a proper company and we were the first to do promenade performances where the audience was an inch away from you. We had music and dancing and it was so exciting. But it was mostly men. There were only three women in the troupe and you just had to go along with it. The bar backstage was always open at lunchtime in those days – you couldn’t rehearse in the afternoon because everyone had had too much to drink!

So it was a different world?
It was very different. When I went to the theater, we would rehearse one play during the day, do another in the evening, and then go home and learn our lines. And when young people say to me, “I’m completely exhausted,” I think, “You don’t know the meaning of the word!”

One change is that women are more likely to play roles that were written for men. They have Old Adam and Corin in As you like it and the servant Firs in The Cherry Orchard. What do you think about it?
I hadn’t done much for a while when I was offered As you like itand I just thought, “Well, let’s try it.” But when it came to Firs, I wasn’t quite sure if Firs could be a woman. But everyone kept telling me it was a wonderful role and I shouldn’t be silly and do it. So I finally did it and I’m very glad I did. I think it’s up to each actor to decide if they want to do it. I would hate to play King Lear, but that’s my business. It really depends a lot on you.

Your marriage also lasted a very long time – how did you manage that?
We didn’t cling to each other. He never stopped me from doing what I wanted to do. He was always very happy when I did everything and the same was true for me and him. We weren’t always hanging around each other. And we often make each other laugh.

What qualities make a professional actor?
Truth. You have to be very, very, very honest, otherwise it doesn’t matter. When I go to the theater, I can’t stand flashy stuff that has nothing to do with the play. It’s just wonderful to see real honesty on the stage.

• Oedipus is from 4 October to 4 January at Wyndham’s Theatre, London WC2