Ageing rockers Bruce Springsteen and Paul McCartney were silenced on Saturday night after over-running at a gig in London's Hyde Park.
Ex-Beatle McCartney had joined Springsteen onstage at the end of the US star's headline slot at Hard Rock Calling, but both found their microphones cut off before they could thank the fans.
Springsteen, 62, had been belting out hits such as Born in the USA and Because the Night for three hours, half an hour after a sound curfew imposed by the local authority was due to begin.
McCartney, 70, joined him at the end to sing Beatles hits I Saw Her Standing There and Twist and Shout, but organisers pulled the plug before they could address the 65,000-strong crowd and they left the stage in silence.
Steven Van Zandt, who plays guitar with Springsteen's E Street Band, later took to Twitter to vent his frustration.
"Seriously, when did England become a police state?" he wrote. "It didn't ruin the great night. But when I'm jamming with McCartney don't bug me!"
Springsteen, who is famous for his long performances, had earlier invited Rage Against the Machine guitarist Tom Morello on stage for two numbers, and fellow US singer John Fogerty joined him for another track.
He also delighted a fan who was holding up a banner asking Springsteen to play an obscure number from his back collection, and listing all the concerts around the world where he had requested it.
Spotting the man, whose song of choice was Take 'em as They Come, Springsteen said: "Tonight, my friend, this is your lucky night. You're going to hear this damn thing."
Paul Simon headlines at Hard Rock Calling on Sunday.
