Blurred lines: When using your script on stage is acceptable

It's unusual nowadays for a lead actor to ask for a prompt in a professional theatre production.

It's even more unusual for a lead actor to walk around the stage holding the script and reading from it, or - when not in hand - seeking it out from the places where it has been secreted around the set. And it is really, really unusual for a lead actor to do this on the opening night of a major new production at a leading London theatre.

But that's what happened yesterday evening at the Royal Court's press night for Penelope Skinner's new play, Linda. The Olivier-winning actress Noma Dumezweni was the star of the show. She didn't know her lines.

To be fair, there were mitigating circumstances. It's a huge part, for one. And she'd had very little time to learn it, for another. Kim Cattrall had originally been cast in the title role of Linda, but pulled out after several weeks of rehearsals on doctors orders. So, with just 10 days to go, Ms Dumezweni, stepped into the breach.

Actors have learnt parts in 10 days before, but perhaps not as big a role as this one, combined with the complicated choreography required to move around Es Devlin's revolving set. The obvious course of action would have been to postpone the press night, but that wasn't possible.

The decision to cast Cattrall had led to the entire run selling out almost immediately, meaning there was no other future performance where they'd be enough spare tickets to hold an alternative press night.

Which left Ms Dumezweni with little choice. Like a souffle yet to rise, she took to the stage last night under-cooked. The audience was forewarned she would be referring to her script - which was a smart move. Because when she did so, about 20 minutes into the piece, it was less awkward for her and us.

But it wasn't entirely comfortable. Lines were jumbled, names forgotten, and pages mislaid. She came out of character for a moment to ask the audience to "bear with me". Our disbelief was no longer suspended.

But having broken the taboo of picking up a script and reading directly from it, she and we settled into the added theatricality of a fine actress learning her lines on the job. And all credit to her. She won the audience round and even when speaking from the script, was able to convince as Linda.

When the final curtain came down there were whoops and cheers and prolonged applause. I suspect the only reason she didn't receive a standing ovation was down to the play's weaknesses, not hers.

It was an unusual masterclass in acting. From a position of great vulnerability Ms Dumezweni was courageous, honest, and impressively professional. She never panicked or lost her cool. The rest of the cast played their parts too, waiting for her when necessary, gently prompting when helpful.

It was strange evening in which we learnt three things: Noma Dumezweni is a brave and versatile actress; the show must always go on; and you can't forget your lines if you haven't learnt them in the first place.