A night at the movies once meant sitting in a dark auditorium, oblivious to the people around you, fantasising about the shadows on the screen. For many it still does. But for the cinéastes of London, film as voyeurism is passe. Now we find ourselves in all kinds of venues - a pub, a club, even a church - watching a stubborn and slightly deranged video projector flashing images on a wall in front of us. The director gives a sulky introduction and disappears to the bar. Programmes of short films are interspersed with a band, a DJ, a comedian, a somewhat strange and mildly terrifying performance artist. By the end of the night, the audience may be pissed and rowdy. They may be snogging each other. This is cinema - underground style.

When I left London four years ago the underground scarcely seemed to exist, consisting solely of the Exploding Cinema, The Halloween Society, and a few co-operatives eking out a frugal living. Settling back last October, the listings sections were full of exotic delights. That month alone saw the Volcano, Pandemonium, Underground America, Sundance, and Invisible Generation festivals. Suddenly the London Film Festival, which traditionally dominates the Autumn period, was surrounded by a number of satellite festivals that threatened to turn it into the staid red dwarf in an exciting and ever-changing galaxy. It would seem that experimental film, as the fashion critics might say, is the new black - England is sporting perhaps the most vibrant and popular underground scene in its entire cinematic history. Even the artistic establishment has been forced to accommodate this trend for experimental cinema: the Tate projected a series of avant-garde films onto the front of the new Bankside building, the ICA gave house to the underground-style Cinergy, while the LFF itself gave up the bid for the first division of international film festivals and included experimental and short film programmes.

Why this sudden change? Stephen Eastwood, one of the organisers of Volcano, explains: "People are much more cine-literate now, through television and video. They're tired of the joke of Speed 2. The blockbuster just doesn't deliver what it promises anymore, so people are seeking alternative experiences." He believes that the rapid growth of the underground since the early 90s has been "a reaction to a loss of creativity in standard cinema through the 80s." As films became more and more expensive, fewer risks could be taken, so the same familiar faces, storylines, and twists emerged again and again. "Narrative isn't the enemy, and character isn't the enemy", says Eastwood, "it's formula." The underground provides a forum where experimentation and innovation are encouraged. Not just in terms of the content of a film, but how it is exhibited and in what environment. The underground puts every aspect of cinema up for reconsideration, due to a belief that mainstream cinema has reached a point of stagnation.

This belief is not unique to a handful of militant filmmakers...