The Specials, Academy, Birmingham

Reunion coloured by a whitewash

Not many tours are morally compromised. But when the Specials spearheaded the 2-Tone label and movement in 1979, they stood for unity in the face of National Front racism and social decay. Thirty years on they are a band you have to take sides on. Their leader and musical mastermind, Jerry Dammers, has been squeezed out and left behind, the bitter climax to six years, initiated by Dammers, of trying to get the group back together. Only the return of Terry Hall as co-singer differentiates this hyped, sold-out tour from previous unremarked partial reunions; musically too, as tonight will prove.

Ill-advised and clumsy attempts by the six Specials here to obfuscate the fact and erase Dammers' core contribution to their music have reached almost Stalinist levels. No merchandise features an incriminating picture of the band then or now. The sole indication that Dammers exists is bootleg posters of their eponymous first album's sleeve sold outside.

The crowd don't seem to notice, cheering explosively when the Specials begin with "Do the Dog". "(Dawning of a) New Era" is followed by "Gangsters", the single seven idealistic young men from Coventry launched that era with. Lead guitarist Roddy Radiation poses on a drum-riser, singer Neville Staple runs on the spot and Lynval Golding windmills his rhythm guitar. Squint, and it could be one of the evocative photos of their heyday, minus the massive stage invasions they loathed.

Only Hall has truly changed. The withering contempt which made him a charismatic teenager has been replaced by modest gentleness. Eyebrows permanently raised, he can still find the rebellious working-class meaning in "Rat Race", understood and shouted back by most here, still being out-run by the privileged as they enter middle age. The almost entirely white crowd shout back the anti-racist "Doesn't Make It Alright" with equal fervour.

Mostly, though, the meaning of songs which once subtly explored alienation are flattened by blank ska-punk versions. 24 songs bullet by in 80 minutes. Subtlety might, anyway, be trampled by the fans' bellowing of every word. But as Golding leads them in "Specials" terrace chants, the band seem equally happy to wallow in basic nostalgia.

Dammers' ambitions for their second and final album – the muzak, soundtrack and jazz-inflected More Specials – are at least attempted. The odd mariachi rhythm of "Stereotype" becomes a shanty, which slips straight into the dark dub and playful brass of "Man at C&A". The brass-players, of course, are anonymous young hands. The great old Jamaican trombonist on their records, Rico Rodriquez, preferred to headline his own night in a Brixton pub the other day, with DJ Dammers. Battle lines have been drawn.

I've never felt so little like listening to "Ghost Town". This was a single of apocalyptic prophecy in the summer of 1981, as its portrait of inner-city decay preceded and soundtracked nationwide riots against racist policing and growing unemployment. It was Dammers' masterpiece, Hall told me in 2007, also portraying the Specials' own decline and fall, climaxing in the perfectly savage split of this "heavy-duty" band after they performed it on Top of the Pops. Those wounds haven't healed. Leave aside that this is a lop-sided, awkward version, and look at where the snake-charmer organ which defined the record is coming from. Not old keyboardist Dammers, of course. But a young man in glasses and flat cap, vamping and gurning in a wild impression of the man whose notes he is playing. The only thing they haven't done to parody Dammers is knock out his front teeth. One look at this grotesque, stupid insult and the charade crumbles. One listen to these skilled musicians, lacking artistic vision but barrelling through the hits, and it gets worse. "Enjoy Yourself" is how they finish, and everyone does, leaving lost in old memories. The present reality, though, is desperate. You'd never know the Specials were special.