Your success, in your own words, has been a "slow burn". Do you mind?
I'm glad that happened to me. I was not emotionally mature enough to accept any kind of success when I was young. I needed to go that long route. Some people are instantly brilliant. The Kenneth Branaghs of this world are ready-formed actors at 23 - he has used his success in lots of different ways - but there are people out there for whom acting is: "Ooh, I can get on the telly and be famous." I felt it was a lifetime thing: this is what I want to do with my life.
Is there a part you've most relished playing?
There's probably a part per decade. Nina in The Seagull, when I was young; as I got older, Masha in Three Sisters; and then Lady Macbeth, Cleopatra. Those are the ones that stick out.
And is there one that haunts you?
Hedda Gabler is hard to crack. I don't even know if I want to, because she was a hard person to live with.
You've become a champion of older women and written a book on the theme. Why?
I wanted another project. It was a preoccupation - the transitions of those strange years called middle age. Who are the role models out there? Why are we invisible in the media? Why aren't we in drama? Why is there so little reflection of ourselves?
How have you been treated in middle age?
The roles that I am asked to play are different and smaller. My skills and experience have increased but I am being asked to use less of them. This isn't just my story: it's echoed by other actors and friends. I'm questioning whether it is a new phase in life or if it's predominantly a reflection of society. It is a biological fact, but what happens to each of us can be very different.
You have continually worked as you've got older. Was that hard to achieve?
I haven't had children and I've only just got married. Work has been the central column for most of my life; it has always been my identity. So I can't tell what it is like for that not to be the case. In almost every line of work, it gets harder just at the point when you think, "God, I actually know something about my profession."
Did the age discrimination case of Miriam O'Reilly at the BBC help your cause?
That was a historic moment. It focused on the inequality of how we respect a man who has accumulated a lot of experience, but when a woman has got to that stage, it's curtains. We'll challenge that now.
Do you feel this government supports theatre?
Maybe I'm a bit cloud-cuckoo but I'm optimistic. I have lived through several funding crises and antipathetic government policies. We don't
admit that we love the theatre as a country, as a nation, as a people. Luckily, each generation brings forth great writers, actors, directors and designers. There's so much talent coming out that has to find a place. Funding is always going to be a struggle.
Is it frustrating to have to keep making the case for the arts?
I find it exhausting, tiring and depressing to have to go through the same old arguments we were going through 30 years ago. It's important that people get their chance. It is an example of what is happening at large with young people - it is much harder to get started. I'm still optimistic that, somehow, talent will out. I've witnessed the survival of the theatre several times when it was meant to be dying.
Do you vote?
I vote, but I don't feel that I'm achieving much when I do. I write letters to people and do old-fashioned things like signing petitions.
You supported the London Philharmonic musicians who were suspended for their protest against an Israeli orchestra playing
at the Proms. Why?
Whatever you think about the politics of any one of the individuals in that group, I don't think that anybody should be allowed to stop people performing.
How is newly married life?
It's an adventure. It's more different than I thought it was going to be. We are only three or four months into it; we don't have a routine; it's never dull. And it's not conventional. It's not like when you get married, start a home and a family - we've already done that bit. We are trying to accommodate our eccentricities.
Is there a plan?
Not really. I respond in the moment. What do I feel like doing now, in relation to what I have just done? I don't shape my career as proactively as people think I do and I have to work with what I'm offered. You can't have it your way as much as people think you can. You operate with the great power of being able to say no, and that's about it.
Are we all doomed?
Of course not. The good guys have got to shout louder. It's always the way, isn't it?
1950 Born in London
1988 Wins an Olivier Award for roles in Twelfth Night and Three Sisters
1999 Publishes Other People's Shoes, an autobiography about acting
2006 Plays Cleopatra to Patrick Stewart's Antony for the Royal Shakespeare Company
2011 Becomes a dame and marries for the first time. Publishes Facing It and speaks on acting and ageing at the Cheltenham Literature Festival on 9 October