You can always rely upon Vamos to come up with something new, and there are a fair number of big surprises in this current show. They have pushed the boundaries of their subject matter and technology further than ever before. The emotions seem more subtle, the use of video is much more essential to the story and, for a dumb show, it’s pretty noisy.

In keeping with writer/director Rachael Savage’s eternal quest for authenticity, a boy actually did climb onto a roof once. With the condition of Attention Deficit Hyperactivity Disorder, he decided the roof was the best place to go for a spot of peace and quiet.

Being told that story by his mother became Rachael’s starting point. For even greater authenticity, she engaged an actor with ADHD, Gavin Maxwell, to play him. Mask mime theatre is shorn of spoken dialogue, so Gavin’s personal experience is surely vital to his portrayal of the condition through posture and movement. The result is mesmerising.

In the play, young Liam is misfunctioning at school. He might be Player of the Year on the football field, but he’s rubbish at everything else. We know this because we see quotes from his school report, and texts from his teachers, projected onto his living room wall. Needless to say, this is of exasperating concern to his parents (mimed by James Greaves and Alan Riley) and domestic friction is a cause of both anxiety and laugher in the audience. For Liam though, the loneliness of ADHD prevails.

The family live in a terraced street and, in a sequence reminiscent of a video version of an Advent Calendar, we open windows on all the neighbours, in their tiny houses, leading their insular lives - respectably reading and making models or, disrespectable, drumming or drugging.

Being old and lonely can have a similar impact to ADHD, so we zoom in on a  lovely old widower Albert, alone with his crosswords and wireless. Both feel isolation but it’s a mobile phone that brings them together. Albert can’t work his, but Liam can. A friendship flourishes.

There are some heartrendingly sweet moments between them as they introduce each other to their worlds, starting with chess and cannabis. Albert is introduced to Tic Tok and a ‘virtual’ headset in clouds of projected bursting bubbles. Liam learns about astronomy, ready for his next rooftop vigil. And they share their passion for the football results on Albert’s old radio. (although I take exception to Manchester City losing!).

It’s in these scenes that Vamos pushes the envelope again.

Regular audience members will have worked out long ago that their performers swap masks to play many parts; but this time two performers in identical masks play the same part, simultaneously. There are often two Alberts on stage at once.

This has been done before in spoken theatre (by Alan Bennett, for example) but in mask/mime it introduces extra fluidity. The story can time shift and concertina. Humour can be had from all three performers playing one game of chess - or both Alberts reacting in mirror image to different instances. Vamos have always experimented with their chosen genre; now they do it more so.

The greater use of video shows us what lies beyond the living room windows. More masked characters pace the street, and are aware of the pending climax of the piece before those inside. It’s clever stuff. It broadens the context of the play. And it works a treat.

On the usual Vamos spectrum of content and comedy, Boy On The Roof edges closer to providing a show with very thoughtful content.  We get a very clear idea of what it must be like to feel isolated, no matter what your age. One of the curses of isolation is the lack of verbal communication; so it is a perfect subject for a play without words.

At one point Albert, with his back to the audience, beautifully conveys his despair with silent heaves of his shoulders; which speaks louder than any words. I was moved to tears.

Four stars

Reviewed by Chris Eldon Lee. Vamos next present Boy On The Roof at the Roses Theatre, Tewkesbury on Tuesday 27 February and Worcester's Swan Theatre on  Friday 8 & Sat 9 March.