Devised by members of the Lyceum Youth Theatre and directed by Mark Thomson, Amanda Gaughan, Christie O’Carroll and John Glancy, Hidden is a one-off, site-specific production which uses the entire Lyceum building as its stage. Tempted by the chance to see behind the scenes, editor Robert James Peacock went along to see what it was all about…

You can nosey round old buildings in Edinburgh at other times of year of course – Doors Open day for one, and the Fringe usually offers a chance for a snoop. But it’s nice to make an occasion of it, and even better to be entertained while you do so. Hidden, a new piece by the Lyceum Youth Theatre offers exactly that.

Devised as part of the theatre company’s fiftieth anniversary celebrations, this promenade piece leads visitors through the shadowy nether regions of the famous building, all the nooks and crannies you never get to see on regular show nights. Taking a cue from its Victorian heritage, the piece first leads us up to attic dressing rooms, allegedly left untouched since the building was built 1880s. Then its down to dark understage storage rooms, filled with abandoned props, and some very scary looking antique dolls.

On the way, we meet waifish orphans, screaming school-children and apocalyptic preachers. A lot of things go bump in the night. There’s screams and shouts, flashes and bangs, disappearances and reappearances. It certainly heightens the senses as you adjust to unfamiliar surroundings.

It does take adjustment too. You’ll find yourself scratching your head as you try and work out what part of the building you’re in. There are staircases in places you wouldn’t know existed, disused toilets, hidden cupboards. And is there an upper upper circle or am I imagining things?

In fact, one of the most fascinating things about it is the glimpse it offers of bygone theatre-going. Bits of the hidden Lyceum haven’t been altered for decades, and as you spot the fading signs and period designs, it’s possible to imagine audiences of other eras trooping through the corridors and the stairwells.

It’s fascinating too seeing some of the unpolished bits of the building. Walls are graffitied, notices have been doctored. Some seem for real (“I’d turn back if I were you” says the sign on the crew room door), some could easily be part of the show (“You’re going the wrong way!” exclaims some graffiti daubed on the peeling paint of a rear staircase).

This is the first youth theatre production ever to run a full week at the Lyceum and it gives a rare opportunity to explore this fascinating building. Even if there are stewards keeping a check on you, there’s still the mildly transgressive feeling of being somewhere you shouldn’t be. Plus the youth company have made very creative use of the space. They’ll appear from all sorts of hidden corners when you least expect. You’re in for a few surprises, for sure.

Hidden is @ Royal Lyceum Theatre, Edinburgh, until Sat 24 Oct 2015