The 39 Steps Wyvern Theatre, Swindon until Saturday

I SAY, old chums... There’s a jolly good show running at the Wyvern this week. It’s a perfect hoot! You simply must go along and see it, what what?

Anyone expecting a serious spy thriller – perhaps having read the original John Buchan novel or seen the 1935 Hitchcock film – could be forgiven for being bemused by the level of riotous comedy in this adaptation by Patrick Barlow, currently on tour alongside a successful West End run at the Criterion Theatre.

But having (shamefully) done neither, I was happily surprised to find myself giggling at the slapstick and sheer ingenuity of a show that is so cleverly put together you can’t help but grin.

For those unfamiliar with the story, our handsome hero Richard Hannay (fair wavy hair, light hazel eyes, very attractive pencil moustache) finds himself on the run, accused of a murder he didn’t commit. His adventures take him to the wilds of Scotland, where he eventually uncovers the secret of The 39 Steps, not to mention falling in love with his immaculately beautiful, if reluctant, blonde companion, Pamela, and saving King and country to boot. Golly!

But it’s not the story that raises the laughs in this show. The comedy is almost entirely elicited from the fact that just four actors comprise the entire cast. Four actors, playing a reported 139 roles (I didn’t count!), in 100 fast-paced, mind-boggling minutes.

There is no room for drifting off here. You need to stay alert to keep up as the tireless foursome swap hats, wigs and accents with lightning speed, sometimes wearing two costumes at once and simply turning from side to side to convey a different character.

Confused? I promise you won’t be, as the actors are so skilled at what they’re doing as to be entirely believeable. Even the absence of major props and scenery matters not at all, as they turn boxes into a train and chairs into a car.

So, old bean, what are you waiting for? Tickets are £17.50, so treat yourself before it’s too late. You won’t be disappointed.