The latest edition of the Edinburgh International Improv Festival was the most successful yet. While the number of acts and shows remained similar to previous years, the attendance and popularity has soared. As co-founder and event compere Jason Perez said, only two shows over the four days were not completed sold out. Perhaps this is down to the boom of Improv in the central belt (with an anomalous outbreak on the Shetland Islands) which has seen numerous groups set up for performance and teaching over the last few years, with different troupes sharing members with a fluid sense of community. Or perhaps the success of the festival has inspired the formation of some of these groups. Whatever the real answer of this chicken and egg scenario, this international gathering has become, within a few years of its inception, one of the foremost improv events in the UK.

We attended the headline shows on Friday 2nd and Sunday 5th March, both of which featured the cream of US performers, several of whom had conducted workshops during the festival, and who have what could be close to a century of experience between them. First up were Sarah Claspell and Michelle Gilliam performing an hour of top-level no-frills improv. With a single word from an audience member – dynamite – the pair set off on four lengthy scenarios. Beginning with the slightly haphazard defusing of a bomb, it was clear why the two are held in such high regard. With no larger ensemble to take any of the burden, Claspell and Gilliam were constantly thinking on their feet at lightning speed. They deftly established the setting of the scenario, the pace, the characters, and even a series of running gags and callbacks.

A case in point is the second sketch in which things get surreal in a car dealership in the Deep South. Gilliam especially is masterful at slowing down a scene to let it breathe, and at finding humour in the gaps between dialogue; very necessary when the scenarios are all over the ten-minute mark. Taking on the persona of a customer who is easily distracted, she even managed to create a catchphrase. Claspell knows when to allow the slack, and when to haul the scene back on to something approaching a narrative track. It’s a great hour in which later scenes call back to earlier scenes and they end by almost looping back round to the start. Apart from the comic skills on display, what is most impressive is just how controlled it is; as with any performers who are excellent at what they do, they really do make it look easy.

Sarah Claspell was back onstage for Sunday’s headline show, and the final performance of the weekend. She was joined by Shannon O’Neill of the Upright Citizen’s Brigade, New York-based Sebastian Conelli, two other veterans of the UCB Theatre Ryan Haney and Achilles Stamatelaky, and Jason Perez for the All-Star Armando. The format for this show is a series of sketches inspired by an initial monologue, which is itself based on a word from the audience. The evening’s monologist was poet Chrissy Williams who kicked things off with a freewheeling series of anecdotes based around the word cake. From there it quickly became chaos. Far more anarchic than Friday’s headliner, the quickfire sketches threatened to fly off the rails at any minute, with the six performers all keen to spin any given scenario off in a new direction.

This was a 90 minutes that was so fast-paced that it was more difficult to pinpoint highlights and individual performances than in Friday’s show, but there were several moments that lived long in the memory. From an embarrassed Chrissy Williams telling the crowd that she was unaware that ‘duck butter’ was an inappropriate title for a children’s poem, Stamatelaky and O’Neill performed as poet and publisher going over a new anthology for kids, featuring titles such as ‘Donkey Punch’ and ‘Dirty Sanchez’. Clearly long-time collaborators, the pair established a deadpan mode of delivery, leaving the humour to be found in the increasingly rude dialogue. In terms of delivery – if not content – it’s not unlike the political dialogues of the late, great Johns, Bird and Fortune. Stealing the show however is Conelli’s frankly deranged, and potentially blasphemous in some countries, version of the Pope played as a demented Italian stereotype. It shouldn’t have worked, and it didn’t make a lick of sense, but it was certainly memorable.

Apart from the talent each possesses, what makes it such a good show is the generosity each shows the other performers. When one hits on something that really works, the rest either let them shine, or pitch in to augment the bit. It’s emblematic of the community spirit that can be clearly seen if one spends any time in the local improv community. That’s borne out by the number of fellow performers in the audience, cheering on their colleagues. Roll on next year.