Queen + Paul Rodgers, Hyde Park, London

On the evidence of this concert, one has to ask where on earth has he been for the last two and a half decades? It is a mini mystery of rock, like the riddle of why John Deacon, Queen's original bassist is not on the tour and seems to have been written out of the script.

The linking of guitarist Brian May and drummer Roger Taylor of Queen with Rodgers is both inspired and odd. Inspired because the voice is so great, and he retains a stage presence. He swings a microphone stand in the same way as Mercury, even if he hasn't got the same swagger and panache, and even if he and the rest of Queen cannot remotely play an audience in the way that Freddie did.

But the pairing is odd because Rodgers in his heyday was to some degree the antithesis of Mercury and Queen. Free were a band for the sweaty university circuit. The fans of their heavy, driving rock and intense ballads, were the "heads", the post-hippies who were, frankly, unlikely to be playing "Bohemian Rhapsody" in their bedrooms. Freddie Mercury was camp; Paul Rodgers, whose sexuality was traditional rock star hetero, was never, ever camp.

This oddity was well illustrated at Friday's concert when Queen's "Fat Bottomed Girls" was immediately followed by Free's "Wishing Well". The first is typically cheeky (excuse the pun), the second moody and contemplative. Yet, somehow it worked. Rodgers did justice to Queen's classics and resurrected his own, with as many people singing along to Free's "All Right Now" as to Queen's "We Will Rock You". And, it was a joy to be reminded that "Radio Ga Ga" is one of the best singalong stadium anthems ever.

The evening was dedicated to London's emergency services. They were given free tickets; and the finale, Queen's "We Are The Champions", was also dedicated to them. Fortunately, we were spared any cloying speeches about the bombings. May said quite rightly that it was better for a band to use song rather than speeches. He, Taylor and Rodgers joined together for John Lennon's "Imagine". May introduced it by saying it was a song written by "the greatest rock star ever." It took him less than a second or two to recall where he was and who he was, and to add: "next to Freddie." On this evening, in front of this audience, he can be allowed that.