Fortunately, there was a loophole in Britain's censorship regime. Acting classes, of course, had to include improvisation. As Johnstone later wrote: "I was giving comedy classes in public and the Lord Chamberlain turned a blind-eye, not quite knowing how to ban a teacher from teaching."
When Johnstone moved to Canada, he dialled things up a notch and competitive Theatresports was born. There are two teams of actors, and a typical game might involve, for instance, playing a situation in a variety of theatrical styles – Shakespeare, Star Wars - suggested by the audience. It is unscripted, involves several games and a nonsense scoring system and allows the audience to boss the performers around. And it's very funny. Whose Line is a version of – some might say "homage to" – the copyrighted Theatresports.
Canadian-born pioneer and practitioner Lori Dungey came to New Zealand because of Theatresports.
"There was a big festival with the Commonwealth Games in 1990," she says. "I came over to perform at that. We did a national tour and I didn't go home."
Theatresports' development was greatly aided by a massive grant – $1 million over three years – from an Australian Bank. The bank is no longer functioning, but Theatresports is, with several of the early performers now part of ConArtists, which has extended the brand to corporate events, schools and long-form shows, such as Austen Translation, an entirely improvised Jane Austen musical. "You get a few suggestions and off you go and produce an hour-long show. It's very good for actors to create their own material."
Dungey was at the University of British Columbia when she was drawn into Theatresports, which gradually took over from other kinds of theatre as her primary performance interest.
"Some actors don't like it," says Dungey. "Some are dismissive. But if you can create good improv, it's the best feeling because you are working with someone else and the audience has two cents in the game. It builds up tension because you're not sure it will work - then they laugh like crazy."
Actors with a capital A, who haven't been dismissive, have included Craig Parker, Oliver Driver, Dean O'Gorman and the late Kevin Smith.
Dungey says Theatresports skills are good for any kind of performers: "I think it makes for a more exciting actor. I think you bring a bit more to the game every time."
To the average audience member, with the average person's entirely reasonable fear of any kind of public speaking, Theatresports is that fear times 10, isn't it?
"It's exciting," corrects Dungey. "You might get nervous anticipating beforehand because there is a fear of failure. Once you get into it, that dissipates. If you can get rid of that, it's great. You can't control if the scene will be good or bad. Most of the time they are good. I always tell students no one dies if they do a bad scene. You pick yourself up and go on to the next one."
It's a quirk of Theatresports that actors and comedians seem equally suited to it. It's how Jeremy Corbett found himself as a performer, starting in Australia then slipping into the scene when he moved back here.
"It was a regular thing at the Maidment Theatre on a Sunday," says Corbett, who did more Theatresports then than he does now. "It was more mainstream here than in Australia.
There, it was done in a fly by night club in Fremantle - that was actually its name: the Fly by Night Club. Here there was sponsorship and it was more organised."
Although it could still be risky, and not just in the theatrical sense. "We had a game where you had to do a scene while one of the team had their head stuck in a bucket of water. They asked me to do it and I thought it would be fine but thanks to the combination of water going up my nose, claustrophobia and a small bucket I lasted about a second."
Corbett says the audience is the key. Not only do they provide the material, they're also a lot more generous when it comes to dishing out the laughs.
"Their expectation is different, because they know you're making it up. If you stumble anywhere near a good joke, it gets 10 times the laugh of a comedy club.
"I was in New York once and managed to talk my way into a comedy club and do some stand up. A Theatresports group did a routine straight after three or four comedians, and it didn't go well. The expectation of the audience was higher because of what had gone before."
Corbett says there's no point trying to store up good "bits" to work into the improv. "I liked to make it as improvised as possible. There were people you'd act with who would throw you a difficult ball – you had to struggle a bit more. I wasn't particularly good at the musical games or the rhyming ones.
"I more enjoyed the ones where you were just thrown into it."
• See Whose Line Is It Anyway? at Wellington Opera House on November 26; Auckland Bruce Mason Centre on November 27 and the Napier Municipal Theatre on November 28.
