Ever since the explosion of the rave scene here in the late 1980s, British electronic dance music has been in a state of impressive, not to say baffling, flux. No other area of the dom- estic pop spectrum has generated subgenres at such a rate or become so adept at inventing intriguing names for them. Over the past decade, we have all heard of — even if we haven’t always actually heard — variants on techno, ambient, jungle, drum’n’bass, 2step, garage and, most recently, grime. The lexicon of clubland never ceases to expand, and the new word to listen out for is “dubstep”.

As the name suggests, it is essentially a modern derivative of dub reggae. Invented by producers such as King Tubby in Jamaica in the late 1960s, initially as a cost-effective way of filling B-sides, dub was a forerunner of the remix that turned up the bass on the featured track and smothered it in echo. The worship of near-subsonic bass frequencies is an important aspect of the dub legacy. But equally crucial to its enduring appeal is the way it likes to slow everything down.

Dub traditionally thrives in the aftermath of periods of frenetic musical activity, to which it offers a soothing antidote. The followers of punk turned to it in the late 1970s, when the constant hammering of ramalama guitars got too much. In the early 1990s, the Orb built a career on repackaging dub for ravers who were discovering a need to take it easy after the manic throb of acid house.

Today, dubstep is finding favour with clubbers seeking refuge from the speedy gabble and percussive scrabble of grime. Having acquired international recognition with the success of Dizzee Rascal, winner of the 2003 Mercury prize for his album Boy in da Corner, grime is now old news in a scene that craves innovation and has been feeding on high-velocity styles since the advent of jungle in the early 1990s.

Some of the producers and DJs now creating dubstep tracks — Skream and D1, for instance — are young relatives of original junglists such as Grooverider. The family connection in their music is apparent if you track down one of the 12-inch singles or compilation CDs that constitute dubstep’s so far limited discography. The spindly synthesizers that embellish the melodic top end of Skream’s popular dubstep anthem Midnight Request Line have the chilly sheen you find in many drum’n’bass tracks. D1’s track Cocaine similarly bristles with the hiss and clatter of hi-hats, a favourite jungle device. The difference, in both cases, lies in the yawning spaces in the music, most obviously in that deep, heaving bass line.

To label this stuff “dance music” is a little misleading. Mandatory dancing, you suspect, may be one of the things this more cerebrally conceived music is trying to get away from. At the bimonthly DMZ dubstep nights at Mass, in a converted church in Brixton, the audience will often stand and listen, or sway gently, to the thunderous sounds of the resident DJs, the Digital Mystikz.

Widely credited with kick-starting the scene when DMZ opened early last year, the Mystikz are a pair of black south Londoners who preside over a mixed crowd that cannot be categorised as black or white. The days back in the 1990s when white males turning up at drum’n’bass nights were viewed with suspicion — as potential undercover policemen — have long gone. Dubstep’s appeal appears, at this stage, to be completely colour-blind. At its other London HQ, the FWD night in Shoreditch, the main man on the decks, Hatcha, is white, as is his mixing buddy, Youngsta. If there is a discernible bias in this audience, it is in gender rather than race: possibly because of the music’s abstract, all-instrumental nature, your typical dubstep supporter is a twentysomething male.

Though the centre of gravity is firmly in the capital, the most interesting music being made under the dubstep banner is down to a resident of Northern Ireland, Barry Lynn, who records under the name Boxcutter. With the support of the Radio 1 DJ Mary Anne Hobbs, he is well on the way to becoming dubstep’s first media star. His album, Oneiric — which means “dreamlike” — was released in April to critical applause. Because Lynn uses a larger repertoire of sounds and ideas, his music sustains home listening better than the stark, skeletal tracks created for club purposes by Skream or Kromestar.

He cites as one of his inspirations the cosmic jazzman Pharoah Sanders, and the best track on Oneiric, Tauhid, is named after Sanders’s album of the same title. While it’s true that the occasional presence of flutes, zithers and chimes is highly reminiscent of his American hero, the unsettling, unpredictable character of Boxcutter’s arrangements calls to mind another maverick of British electronic music: Richard James, aka the Aphex Twin.

The Cornishman James was to the ambient scene of the 1990s what the Ulsterman Lynn is to dubstep today — a musician whose individuality seems to be partly nurtured by his separateness from any scene. Lynn has said that he likes living at a distance from a big city precisely because he doesn’t feel constrained to represent anything “urban” in his music. So, if there still is such a thing as an “underground” where youth culture is concerned — and dubstep probably qualifies as belonging to it — Brixton and Shoreditch aren’t the only places to look for it.