London is full of interesting buildings that we visit every day. Unsurprisingly, you may visit a building hundreds of times only ever to see half of what has to offer and never its more interesting and hidden facets.

Take a theatre for example. As an audience member you visit the box office, the foyer and then you take your seats. Perhaps you visit the bar during the interval, but that’s where your journey as a visitor ends. You may have had a wonderful night watching a performance, but some of the most exciting parts hidden at the heart of the building – the dressing rooms, workshops, backstage areas – you may never get a chance to see.

Open House London is one of those rare weekends you get to experience all that and more totally for free, and it’s not just theatres who sign up to take part.

A recent weekend saw listed buildings, museums, theatres and even residential properties throw open their doors for Londoners and tourists to experience in a cultural through the keyhole style event.

Although it would have been nice to nose around somebody’s stunning home, I was lucky enough to join a tour that ticked all my boxes in showing me the other side of one of London’s most iconic buildings both architecturally and culturally; the National Theatre.

The 45 minute tour took us into the auditorium of the 400 seat Dorfman Theatre, backstage to the workshops that produce the incredible sets, scenery and props for all the NT’s in house productions and into an area affectionately known as ‘drum road’. Drum road is the back stage corridor down which all the theatres props and scenery are wheeled before being loaded onto the five story revolving drum of the 1,200 seat Olivier Theatre stage.

I’ve seen countless productions at the National but this is the first time I’d crossed the threshold between what the audience see and what the artists see and it was fascinating.

There weren’t enough hours in the weekend to enjoy all that Open House London had to offer, but I felt my time was spent wisely wandering through the bowels of the brutalist National Theatre building.

If you missed this year’s Open House London but like the sound of getting a peek back stage at the National then fear not, they have tours running weekly (theatre tours, architecture tours and costume tours) throughout the year – although these cost a small fee.

Visit the National Theatre website here for more information about tours and visit the Open House London website here.