Media playback is unsupported on your device Media caption Watch Lisa Dwan's behind the scenes tour backstage at University of Reading

Actress Lisa Dwan explains how she performs one of theatre's most challenging roles, as Mouth in Samuel Beckett's short play, Not I.

As stage plays go, there's nothing quite like Samuel Beckett's Not I.

In a pitch-black space, a disembodied female mouth floats 8ft (2.5m) above the stage lit by a single beam of light and speaks, as Beckett directed, "at the speed of thought".

It's like driving down the motorway the wrong way with no handbrake. Lisa Dwan

When the piece was first performed, by Jessica Tandy in New York in 1972, the dramatic monologue lasted about 22 minutes.

Billie Whitelaw, personally coached for the part by Beckett, performed it in 14 minutes at the Royal Court in 1973.

Fast-forward to 2013, where Lisa Dwan does it in nine minutes - the quickest it has ever been performed.

"It's like driving down the motorway the wrong way with no handbrake," says the Irish actress, who first performed the piece in 2005. "It's absolutely terrifying and it doesn't get any easier, but it's almost the most exhilarating role I've ever known."

Image caption Lisa Dwan with the original Not I manuscript, at the University of Reading

Dwan will perform Not I at the Royal Court later this month to mark the 40th anniversary of its UK premiere.

"Billie's name is synonymous with the role," admits Dwan, when we meet during a performance at the University of Reading, home of the Beckett Collection.

"I'm only able to do it because Billie did it. In many respects she broke the psychological barrier for the rest of us too. She's sort of the Roger Bannister in the Beckett world."

Whitelaw once likened the role to "falling backwards into hell", and, seeing Dwan's preparations, it's not hard to see why.

With her face plastered in thick black make-up, she is blindfolded, her head is covered with tights and fastened through a hole in a wooden board.

"The piece is so physically demanding that my whole body vibrates, so in order for me to stay in the spotlight, it's necessary to be strapped down," explains Dwan.

"There's a lot of sensory deprivation - I can't hear or see - so I usually meditate before I do the piece. I take it very seriously. When I'm rehearsing at home... I strap my head to the banisters."

'Verbal diarrhoea'

According to Beckett's friend and biographer Prof James Knowlson the playwright was very specific about how Not I should be performed.

"One of the crucial things is that it should go at speed," he says. "It's meant to work - in the words of Beckett - on the nerves of the audience, not on its intellect.

Beckett just sat back in his chair - absolutely spellbound Prof James Knowlson on the author's reaction to seeing Billie Whitelaw's Not I on film

"You get these fragments of this sad, lonely, loveless life and you try to piece it together as she is trying to piece it together."

It is, as he puts it, a case of a woman who - after a lifetime of virtual speechlessness - has "verbal diarrhoea".

Prof Knowlson recalls Samuel Beckett's reaction when they watched Billie Whitelaw's filmed performance together in a private viewing studio. "Beckett just sat back in his chair - absolutely spellbound. He had one word to say to Billie afterwards: 'Miraculous'."

He also notes how the strong visual image of the mouth has become integrated into popular culture.

"You have seen it copied so many times on television. It's become a kind of staple, we almost take it for granted that you have a mouth with the lips moving as part of an advert."

Dwan performed Not I at the inaugural Enniskillen International Beckett Festival last year, while this year's programme includes Neil Jordan's multi-screen film installation of the work, featuring Julianne Moore.

Dwan's performances at the Royal Court will be followed by a screening of an interview with Whitelaw on her experiences of performing Not I, as well as an audience Q&A.

Whitelaw, now aged 80, tutored Dwan in the role after they were introduced in 2006.

They became good friends and Dwan recalls going round to Whitelaw's house, where she would perform the monologue in her kitchen. The actress acknowledges that one day she will pass on the baton.

"When I first performed it I was doing it in about 12 minutes and I was worried I was going too fast. Billie helped me with various notes that Beckett had given her, such as how to use the alliteration as a springboard. Now I do it in an around nine minutes.

"My relationship with Billie has been a complete privilege and similarly I'd love to pass on the notes to another actor when the time comes."

Not I is at the Royal Court Theatre 21-25 May in the Jerwood Theatre Downstairs. The Happy Days Enniskillen International Beckett Festival will take place 22-26 August 2013, in Enniskillen, County Fermanagh, Northern Ireland.

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