Teatro Entre Escombos (literally, Theatre Amidst the Rubble) have brought their tragicomedy The Mole and the Worm to London, and it couldn't impress more with its quirky humour and poetic language. Not many could pull off physical clowning in a play rife with sex and death, but this multicultural collective have found a wonderful interplay between its two leads that makes this sweet little play a delight to experience.

The play opens with a spelunking Spaniard swinging in from the ceiling - he is exploring a cave complex, but recoils when the latest hole he's trying to squeeze through turns out to be the nether regions of a woman who appears to have fallen in. However, it soon becomes unclear how long she has been in the cave - from what she says, she could be 50 years old, 100 years old, or as timeless as the rock she has started to resemble. As his rope is pulled down accidentally, the pot-holer has to accept that he too might be stuck in the cave, and comes to terms with his own mortality, as well as the possibility of spending the rest of his life with this rock-woman.

If that didn't make it clear, the plot is extremely peculiar. Constantly swinging between surreal humour and heavy pathos, it's a strange play to get your head around: the humour is often crude, but fits perfectly with the childlike innocence of the woman, and ties in nicely with the bizarre leaps the story takes. It's a masterclass in finding a style of comedy that balances perfectly with the story, and Lowri Jenkins (the writer) deserves plenty of praise for this as well as for the sadness and poetry of her script. Scenes where the characters are calm feature wonderful, quotable lines and their dialogue is wholly natural. If we also consider that one of the leads is Spanish and delivers most of his lines in broken English as well, it's a huge achievement.

While the piece is clearly written for these two performers, it's no small achievement for either. Javier Ariza has plenty of moments to shine physically, from his first entrance via a rope from the lighting rig to his impromptu dance routine, but it is his vocal delivery I admired most. In a second language, with a thick accent, he is still totally comprehensible, even when starting the play off in Spanish. He is so in charge of his diction that he can make what he is saying clear to a predominantly British audience without much effort. Amy Gwilliam has less to do physically, but her slow, brittle movements are a nice counter to Ariza's physical virtuosity - a quiet subtlety, combined with a clear, rounded delivery. These two seem to have been made for each other.

It's just outstanding, from start to finish. Excellent performances, a fantastic piece of new writing, and an exciting new company I can't wait to see more of. If you'll indulge me, I'll describe a moment that encapsulates just what makes this work: the show opens with the caver swinging onto the stage. It's so original and odd that it draws a laugh and gasp. He looks cool, calculated. He adjusts his light, kicks off - and catches himself in his rope. We gasp - but he's getting more and more tangled, until he's just a ball of rope and limbs. And there isn't a dry eye in the house.

The Mole and the Worm, at Theatre503Chris Hislop reviews The Mole and the Worm at Theatre503.5