We meet in a restaurant in Primrose Hill, one of London's last remaining "villages", where there are no parking meters, where there's still an ironmonger and where Fiona Shaw still lives in the small flat she bought many years ago.
She should move, she says. As one of the English theatre's most sought-after performers she knows it would make economic sense. But as her scrubbed face and unruly hair attest (put a veil on her and she'd look like a nun) such worldly considerations are of little interest. She's happy here. Perhaps because Primrose Hill is as close to Cork as you get in London.
It's nearly 20 years since Fiona Shaw left home, the insurance of a philosophy degree from UCC tucked into the pocket of her tweed skirt ("I had this idea that London was smarter and therefore one wore one's best clothes. Everybody else was a punk.").
Her destination was London's Royal Academy of Dramatic Art. "I wanted to be trained. There was no training in Ireland and the whole idea of doing something that was so hard to do, I felt I should be trained to the level at which I wanted to be able to achieve it. And when you come from Cork - well, my life experience was already quite inadequate to the task."
It's clearly a touchy subject. Although she has just been appointed Professor of Drama at Trinity, Fiona Shaw remains wary of the antagonism she senses still lingers at her decision to "by-pass" Dublin all those years ago. "I think in retrospect there seems to be a much greater plan to the way one's life goes than there is. I had no intention of staying in England." But Shaw was on fast track with the Royal Shakespeare Company, her pointy face and machine-gun delivery a perfect embodiment of the wise-cracking heroines of classical comedy, from Shakespeare to Sheridan.
Then in 1989 Deborah Warner, one of the RSC's young cutting-edge directors asked her to do Sophocles' tragedy, Electra. It was a performance no one lucky enough to have seen will ever forget and won her a Lawrence Olivier Award. Electra eventually went to Derry, but Fiona Shaw rarely been seen in the Republic: in Hedda Gabler at the Abbey in 1991, and in Cork and Dublin with her extraordinary solo performance of T.S. Eliot's poem of urban desolation The Wasteland.
Apart from a film role in Jim Sheridan's My Left Foot, that was hardly mainstream stuff, so it's no wonder that over here she's still comparatively unknown. However Neil Jordan's film of The Butcher Boy will change all that as Shaw's unique mix of steel and comedy come gift-wrapped in the pivotal role of Mrs Nugent, the object of young Francie's murderous scorn.
As we talk about Jordan, Shaw's mobile face goes into overdrive, hands fly and words tumble over themselves. "I beg and pray every night that it's just a beginning. He's a master, and when you're with him you know it. He's like Picasso's centaur, you get a sense memory that you're with an atavistic creature, then out of it pours the most delicate-minded, fastidious, accurate, truthful eye and voice. The level of the machinery of his achievement I find really breathtaking. Not that it's effortless, but it's like a combine harvester of ability. In fact I get terribly shy with him because I feel overpowered by the size of who he is."
The relationships Fiona Shaw builds with her directors are central to the risk-taking she sees as essential if the theatre is to survive. "It won't if it goes on pretending to be what it was. It needs to know what it is. Like painting. Painting had to move on from being a recording medium when photography killed it. And film has killed that kind of theatre." It's a question, she says, of going "beyond the wall".
"With comedies it always ends at the joke. It's like a wall, it stops. Bang. But with a tragedy you go through the wall. You go into another place." It's a difficult journey to do on your own. And it's from this need for a fellow conspirator that the partnership of Shaw and Warner continues to flourish. "We introduced something to each other. She egged me on and in turn she couldn't believe where I was taking her. After Electra I think we both realised we had somehow been up the Amazon and then of course you want to go somewhere else, to the unknown, because the unknown is always more attractive than the known." And more frightening.
"I know that I have always been drawn to danger. I come from a very protected and protective world. Somewhere I think maybe it is my way of being dangerous without in fact any harm being done."
The danger may be physical, as in Machinal, written by Sophie Treadwell and directed by Stephen Daldry three years ago at the National Theatre, where she had to work high up above the stage; or emotional, as in Richard II, also at the National, directed by Warner. ("We both left the RSC and went to the National at the same time. Very quickly there was a flurry of interest: you only had to do two things together and people saw a pattern. And then there was a pattern.") No-one anticipated the uproar that ensued from the British press that a woman would dare to play a king of England.
"Richard II was the most brave thing I tried to do. It felt like diving off a diving board and I wasn't at all sure if there was any water in the bucket, but I had to try and see if there was." It was the first time that Shaw, as a performer, had been stung by bad press.
Then there was Beckett's Footfalls, in which Shaw paced the rim of the balcony of the Aldwych theatre, her tall body stooped so as to miss the balcony above, while the audience in the stalls looked up and held their breath. The Beckett estate would have none of it (she also had the temerity to be dressed in red while the text stipulates grey) so the production was pulled off after only five performances. ("I can completely understand the argument, but a play has to be released into where the theatre is. Otherwise the play will die. You will kill it. Shakespeare was never damaged by bad productions.")
Then came The Wasteland, which Shaw and Warner funded themselves and which has taken them to a disused gin factory in Canada, the Magazine Fort in the Phoenix Park in Dublin, an abandoned cinema in 42nd street and most recently London's oldest surviving music hall (Wilton's, in the East End).
Fiona Shaw's insistence on pushing on "beyond the wall" is not limited to the stage. Last year she spent two weeks in an enclosed order of silent nuns as a novice - following up an idea from the BBC. "I wanted to see once and for all whether I had that latent vocation that you wonder is the other side of your wild side." Although she is no longer goes to Mass, the legacy of her Catholic upbringing runs deep. The furore over Richard II left her feeling she had done wrong ("that Catholic thing"). Being feted in New York for The Wasteland by "the whole literary world, the painting world, the social world, the Vanderbilt world" was also hard to accept. "I enjoy it with a third eye but I can't turn it off. So it was like being Alice. I kept thinking, Dinah will want to be fed soon, I must get back."
She entered the order immediately on return from New York. "One night I was having dinner with Jasper Johns, the next I was in this convent. It was not easy." For a famed tragedienne, Fiona Shaw is not remotely serious ("I have a severe face and if I'm not careful I terrorise people, so I have to smile.") Yet the nature of theological need continues to trouble her. Those two weeks were long, hard and extraordinary. "The great thing about religion is silence. But it's not the silence of the grave. It's the exact same silence as the silence before a play starts. It's the silence of anticipation."
In May Shaw returns to the National Theatre in London for an updated version of The Prime Of Miss Jean Brodie directed by Phyllida Law and she is looking forward to getting back to "the joyous world of comedy, the joy of laughter". Muriel Spark's Edinburgh, she says, perfectly captures the ambivalence of life in a provincial town, "it's potential difficulties matched by an immense richness that you can only get in a small world. I am very glad I wasn't born and brought up in London." Children who are, she says, know too much.
"So they find it very difficult to go anywhere else. Whereas to me, the whole world seemed magical because I had this great rooting in a small city. There is this mantra of being able to recall the names of shops, just saying these words brings a fantastic cloak of immense comfort and conjures entire worlds that are nearly gone. It makes memory incredibly sweet, incredibly rich and I know it's an enormous fuel when I'm dealing with plays of immense complexity, because in the end as Joyce tells us, all worlds are in a small world. It is not that we aspire to be like poetic characters. Poetic characters are mirrors of who we are and the classics should be stolen by universities, to feel alienated from and eventually to learn how to approach. All of art is about us and we are about it. The smaller the world you live in, the more you realise it."
Fiona Shaw begins filming in an adaptation of Elizabeth Bowen's novel The Last September, directed by Deborah Warner, in the autumn