Joanna Lumley: Strange meeting

Would you take a bullet for Joanna Lumley? I found myself considering this question the other night in Sheffield when our interview was unexpectedly interrupted by an offensive weapon. One moment she was fondly remembering Sheridan Morley ("a darling man. Bloody good writer, too"); the next, I was mentally calculating how, if need be, I could leap to shield her from a trajectory of lead and shattered glass. Or should I try to grapple with the assailant? It's hard to know what the etiquette is for protecting national treasures in impromptu firearm situations.

Before we saw the man with the gun, the interview was running smoothly. We were sitting in a wine bar near the Crucible theatre and Lumley, stylishly dishevelled in an outsize pinstripe jacket, was sitting back with a G and T. From the outset, she was all you hope and expect she'll be: very warm (the theatre's young media officer gets a "sweetheart", and you can see him swell with pride), clearly a good egg (troubled, always, by social conscience - "the people weighing on my heart at the moment are the carers, who are tired out by looking after invalids, poor as rats and given no recognition for their work...") as well as pleasingly gung-ho. "Shall we have a ciggie? See, we smoke and we're not dead, are we?"

She has come straight from rehearsals for The Cherry Orchard, directed by Jonathan Miller. "When someone offers you that, the first thing you say is, hurrah, I'd love to do it. The second thing you say is, who's the translation by?" (The third thing you say, perhaps, is "Can we make sure there are no lone gunmen around?" - but more of that later.) The translation is by Pam Gems - "a lovely one, that sounds just like normal speech" - and Miller has been given permission to "kick the text about a bit, so it's as fresh and naturalistic as possible. We're working on a great big apron stage, so, immediately, you're not hidden behind a proscenium arch. This isn't Chekhov handled with kid gloves. It's going to be just like real life: so, so real. That's what I love about Chekhov."

But real life is what is happening at the table next door while you are busy doing interviews. A few seats away from us a big, tall man, clearly on edge, is shifting in his seat, a heavy black bag on his knee.

Lumley says her Ranyevskaya is "coming into focus, gradually". "She's charming and thoughtless and hopeless and infuriating. She loves going to gay, bright Paris and seeing Offenbach operas". All the greats have played the feckless aristocrat who dances as she loses her family's cherry orchard: Vanessa Redgrave, Peggy Ashcroft, Dorothy Tutin, Judi Dench. Lumley herself took the role at Dundee rep, 20 years ago. "But with the classics it's brilliant to be able to go back and have another go because more life has gone on, you've become a different-ish person."

Now we are a couple of cigarettes in, and it is dark outside. There is a note of festivity in the bar because of Lumley; you can catch people looking at her and back at each other, as if to say "Patsy from Ab Fab is having a drink at the neighbouring table. Fancy!" The only person who doesn't appear to have noticed her is the big tall man, rummaging in his heavy black bag.

"And Jonathan Miller has been a hero for ever," she continues. She saw him in Beyond the Fringe, and then accosted him one day in Vogue House. "I used to be a model and I was doing a shoot there with David Bailey, I think, and Miller walked by in the corridor. I scuttled after him and said how much I admired him. He just looked at me like I had crawled out of a swamp." Perhaps it was the false eyelashes.

Lumley is good at trusting directors. "My husband Stevie is a working musician and a conductor, so I understand how they control the stage and the orchestra, the pace, the dynamics, everything. They run it. They're the Maestro. I do respect that."

Miller's doctorate in neuropsychology informs his direction, she says. "Look at this." She makes a small, definite stroking movement on the tabletop, flattening an imaginary crumpled sheet. "It's what people do, he says, when they've had an absolutely massive shock. It's like a physical symptom of trauma. It's what Ranyevskaya's going to do when she finds out Lopakin has bought the cherry orchard. It's the most humiliating, ghastly thing that could happen. His father and grandfather were serfs and couldn't enter the house. When she hears the news she just sits there fiddling like that with her skirt."

The man at the next door table is swigging back another tawny drink - whisky and water? - while conversation with Lumley rambles delightfully on, from Chekhov's proto-ecology ("the destruction of the cherry orchard - just like our dilemma with green field sites - people need homes, but not here! Not in my back yard...") to her brisk approach to ageing. On memory: "I think it's important to be strong with yourself and practise remembering numbers and security codes and not drift into loopy land." On looks: "If you're going to be 60, there's no point pretending you're 30. You're not going to get cast as a 30-year-old. It's not going to happen, darling. They've got 30-year-olds."

Sometimes there are unmistakeable tones of Patsy in her voice. Does she hear them too? A faraway smile. "Not really." There's a lot of Ab Fab she's never actually watched. She was in it and that was that. "Sometimes I don't know what people are on about when they quote it to me."

A sudden clatter from the next table. Lumley glances sideways casually. Then her stare intensifies. She goes rigid. She mutters, even more breathily than usual. "He's got a gun. A great big handgun. It just fell on the floor, out of his bag."

The man is now zipping up his bag, looking furtively round the room. "Shall we leave right now? I ask in a small voice. But Lumley is thinking along different lines. "I tell you what," she says, voice ripe with repressed excitement. "It's too intriguing. I wouldn't want to involve you and put you in danger ,Hermione, but shall I go over and say: we couldn't help noticing your gun, what's it for, and should you be carrying it?"

At this point, the New Avengers theme tune should have started playing. Or curly wiggly things should have danced across the room, like one of the special effects from Sapphire and Steel. But instead I do the only thing I can think of doing, which (pathetic, isn't it?) is going to the bar and buying some crisps.

Maybe while standing at the bar I started straightening an imaginary crumpled sheet with a small definite stroking motion. Finally I get out my phone to call the police, but a worried young girl who also saw the gun is standing there, about to do just that.

First she asks, "He's not Joanna Lumley's bodyguard, is he?" I look back to the table, and see - oh God - that Joanna is now sitting next to the gunman, chatting. She has magic pluck, this lady. "This is Philip," she says calmly. "He says he's only carrying it for his own protection." She shoots me an alarmed look. Then, "He's from Kerry."

"I'm here on a job," says Philip. "Not a job using that thing, I hope," retorts Lumley. Philip nods, laughs. He seems a bit wired, but very pleased to talk. Dropping the gun seems to have been a weird attempt at a conversation starter. He shows us pictures of his children. He doesn't know where he's going to stay tonight. Knowing the police are on their way I have a pretty good idea. Lumley is warm to him, suggests a hostel up the road, but keeps her distance. Compassion is clearly bubbling up within her for this troubled man, even though her judgement says to keep away. Then Philip disappears to make a phone call.

"We're in an entirely different movie now, aren't we?" she says, and we laugh nervously. She's impressively cool about the whole thing - "I live in Stockwell and people carry all sorts of things there. It's no good being afraid. You find fear within yourself and you need to recognise it, address it and let it go". She is reassured, though, when I tell her the police have been called. I can't help thinking of what Chekhov wrote - if a gun appears on stage, it must go off.

"But it doesn't. The gun in The Cherry Orchard doesn't go off," she says. "Pishchik gets it out, shows it around and puts it away again. That's it." Theatrical convention insists a loaded gun always goes off; great theatre does something different. But what will happen tonight?

Philip strides back and sits down at our table again. In theatre, suspense tends to build in some kind of controlled arc. Here, it leaps up and down like a broken cardiogram. "So what do you do for a living then?" he says to Lumley. First he carries a dangerous weapon, then he doesn't know who Joanna Lumley is. What is this man like? There are huge posters of her all over town. He must be the only person in Sheffield who doesn't know who she is. Just when I think things can't get any stranger, Jonathan Miller walks into the wine bar.

"They know from the very beginning that the cherry orchard has to be sold, no? But they think it will be kept as a cherry orchard." He gives a cursory greeting to me and the gunman and starts to thrash out a plot point with Lumley. "In the middle of act one they know it could be cut down to make suburban holiday homes..." Philip the gunman says it sounds like quite a play. He insists on buying Jonathan Miller a drink, and is very disappointed when he only wants a coke.

"Is this chap with you?" Miller says to me. While he is at the bar Lumley and I whisperingly try to fill Jonathan Miller in on the situation, but he doesn't seem particularly exercised by it. He would rather talk about the book he is carrying, The Metaphysics of the Origin of the Species. ("I have been fascinated by our knowledge of evolution for some time...") or his TV series on atheism, which is about to be shown in the US, or his cultural Jewishness. "I think I am more in sympathy with Jewish religion rather than Christian or Islam because it has no concept of afterlife." Back at his side, Philip nods in jittery agreement: "The men in Mossad, now they were great fighters." Miller looks thoughtfully at him.

I am torn between a desire to evacuate us from the pub and get these two legends to safety and the sense that doing anything sudden or obvious would be wrong; it's a volatile situation and to keep talking is the best thing to do. And also, quite honestly, I want to keep talking because it is just so interesting. Miller is on his Cherry Orchard now.

"It's going to be like The Office." (Now he says that, of course, it's obvious - Lopackin failing to propose to Varya is so similar to Tim failing to ask Dawn out...) "What I want to do is make these characters footling. Flawed and ordinary and mundane. The critics will say I've taken away their romance. I've swept all the linguistic rubbish back into the play - the interruptions, hesitations, overlapping. Before people had tape recorders they never realised how unfinished and ragged sentences were. Or at least no one wanted that stuff in a play."

"But we do now," says Lumley. "Don't you think that with reality TV and everyone watching Big Brother, you can't stick with being dogmatically theatrical? The old formulas don't work any more."

And perhaps the old formulas for interviews don't work any more either. If a gunman comes into a room, he must be written about. Lumley is called over to the bar to take a phone call. She comes back and says in her graceful way that it was her husband and she really ought to go; so should we all. We leave Philip with his whisky and his heavy black bag - 'Bye, Philip, see you later!" - and head onto the pavement,

"It's not true!" Lumley explodes. "I had to say that. It was actually the police on the phone telling me we had to evacuate the area! What a mad strange life this is." Indeed. We say goodnight, and go our separate ways. According to reports the next day, armed police then arrived and took the man away for questioning.

The gun, it appears, did not go off.

The Cherry Orchard, The Crucible, Sheffield (0114 249 6000). 14 March to 7 April