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I go to the fridge for milk, the garage for petrol and the vet to fix my dog. It's a conventional approach to life, but it works.

If, however, I want to go to see some of the latest and most exciting theatre, I have to spend hours rummaging around for a pair of walking boots, a raincoat with a hood and an up-to-date Ordnance Survey map.

Thus attired I set off, with my copy of tucked under my arm, for some God-forsaken location which I can guarantee will be remote, bleak and perishingly difficult to find.

If, and it is always an if, I succeed in tracking down the "found" space in question, there is then the whole palaver of identifying the entrance and once within the "theatrical landscape" of differentiating between players and punters.

This is theatre, but not as Larry knew it. It is the world of immersive theatre, also known as promenade theatre or site-specific theatre; basically theatre that is not taking place inside a theatre.

It's not a new idea, but boy is it popular right now, with both producers and audiences. Such is the proliferation of site-specific theatre that it must be crossing the minds of those who run the Olivier Theatre Awards to add it as a new category.

Last night I went to the opening night of , a new opera by the German composer Torsten Rasch commissioned by the (this event is now sold out).

It is a co-production between ENO and , a theatrical company who specialise in site-specific, immersive theatre.

ENO are supplying musicians and singers, while Punchdrunk provide actors and dancers and direction by their artistic director Felix Barrett.

Felix had said he wanted to challenge the form of opera, to break it open and place the audience at the centre. On this ambition he well and truly delivers. In this production you don't go to the opera, it comes to you.

The action takes place inside a characterless disused grey office block situated in a desolate urban landscape at the far easterly end of London City Airport.

At least the office block was characterless before the Punchdrunk crew set their gothic minds to turning it into a dimly lit network of smoke enthused Dickensian spaces in which Count Dracula or Count Basie would have felt equally at home.

Immersive theatre is aptly named. Sitting back in a comfy seat and nodding off 10 minutes into the production is not an option.

Firstly there are no seats and should you be unwise enough to stand still for too long the chances are some peasant will appear from nowhere making you jump and thereafter jumpy.

For this production you are made to wear a white Venetian mask and told quite firmly not to remove it from your face. An instruction that might be bearable for the clear sighted, but those of us with specs it is an impossibility.

Either you wear them outside the mask which means they will fall off and be trodden on, or you put the mask over them which has the same sensation as the school bully spending an evening pushing some hard plastic into your face.

The other problem with the masks is they restrict your peripheral vision to such an extent you end up barging hopelessly into other theatre-goers like a drunk on the train.

Or worse, frankly, they barge into you. So a 1980s jacket with a decent set of shoulder pads and a pair of shin-pads for when you walk into the edge of an unsighted box are advisable.

But once immersed, the whole thing becomes beguiling as you follow the action around an array of ominous corners and floors.

Or it does if you have guile. It is possible, if you are particularly dull, to stand in a space, move occasionally and thus miss out on all the action. Still, you'd go home on top of your e-mails.

But if you are sensible (follow one of the conductors) the experience, and I choose this word carefully, is thrilling. To be surrounded by some of the most talented musicians in the country, playing a previously unheard score, sung by an excellent cast amid extravagantly weird sets is thrilling.

Unlike an opera in a theatre where the music and singing are the focal point of your attentions with the acting coming a distant second, the Punchdrunk immersive experience relegates the music to something more akin to a soundtrack as the action taking place around you.

The acting and action become the driving forces of the piece, along with the constant need to be on your mettle to ensure the cast doesn't go one way and you the other.

Claudia Huckle is compelling and convincing as the Duchess of Malfi, a role in which she is asked to sing and act in a manner she has not encountered before.

The rest of the cast, at least the ones I saw (there were plenty of others in distant corners acting out accompanying scenes) equipped themselves with poise and presence, especially Andrew Watts playing the Duchess's incestuous twin brother with grotesque glee.

I asked John Berry, ENO's artistic director, if he planned a cast recording of the opera. He didn't. But then went on to say that he could imagine the piece being presented as a straight opera in the Coliseum.

Now, that would be counter to the original concept, but I can see the merit in the idea. Having been totally absorbed by the action last night, I would now like to be given the chance to see the music foregrounded and have the chance to listen to it properly.

But the thought that most struck me last night was where else in the world could this work have been commissioned?

Which other country has an arts scene so confident, adventurous, ambitious and thoughtful that risks such as this production are not only seen through, but executed with such aplomb? The answer in my experience is nowhere, the UK leads the world.

But for how long? According to the ENO it is this sort of avant-garde production that will cease once the coalition government's cuts are made later this year.

Or, as someone put it last night, "this is the end for programming like this, there will never be another season like it." I hope they're wrong.