MC5/Primal Scream, Royal Festival Hall, London

For once, Primal Scream were happy to play second fiddle to their heroes – and, in the end, raised their game enough to play beside them. The band were last upstaged when Basement Jaxx took a Glastonbury 2005 headline slot above them after Kylie Minogue pulled out. Bobby Gillespie threw a hissy fit then; tonight he was more muted. After all, while Gillespie's stylistic magpies flit from one look to another, the MC5 have staked their claim as genuine anti-Establishment rabble-rousers.

The FBI would not bother to tap the Scream's phone lines, but then the Motor City Five were around when tanks were storming Detroit's streets in the 1967 riot. Where the two bands do share common ground is in a relaxed attitude to line-ups. Singer Rob Tyner and guitarist Fred "Sonic" Smith, then married to Patti Smith, passed away in the Nineties, around the time that singer/guitarist Wayne Kramer and bassist Michael Davis met up in prison (serving time for drug offences). The surviving members re-formed in 2003, and performed with the likes of The Cult's Ian Astbury and Motörhead's Lemmy. Since then, the group have toured sporadically as what Kramer calls a travelling circus.

The Scream, meanwhile, pick and mix members as their tastes dictate. Thankfully, Gillespie has dropped the bootlace tie that accompanied the Faces shtick of the band's previous album, Riot City Blues. His slim frame, dressed all in black, suits the cleaner lines of their follow-up, Beautiful Future, which features the same line-up as the last album, with youthful guitarist Barrie Cadogan looking very much the Keith Richards of the party. Their forthcoming single, "Can't Come Back", is pleasingly stripped back, while the louche "Uptown" and metronomic "Suicide Bomb" suggest newfound range.

So what? suggests MC5's swagger as they emerge. Kramer looks like a seedy Hollywood agent, Davis like Frankenstein's monster after a fight with a bull. Any suggestion that the band might be resting on their laurels is blown away by the garage punch of "Ramblin' Rose", which precedes a relentless assault from straight blues through proto-punk grind. Though they cite Sun Ra's free jazz as an early influence, these tracks suggest more a Midwest Lynyrd Skynyrd. The current guest vocalist, William DuVall, fronts grunge survivors Alice In Chains, yet here he convinces as a soul power singer – he even has his own Tyner-like afro.

When the two bands join each other on stage for an extended encore, Gillespie wrings out every ounce of sweat to match DuVall. It makes for a spectacular "Moving On Up" – even Kramer starts dancing – and ends in a free-form jam. The icing on the cake, though, is the appearance of MC5's once estranged mentor, John Sinclair, immortalised in song by John Lennon after being given 10 years for possession. Imperious, he recites a poem on the meaning of jazz. You have never seen Gillespie smile so broadly.