When Prince wrote the words "tonight we're gonna party like it's 1999" he was thinking about the end of the world. Last night, when he kicked off the song, the lyrics just meant 'let's party like we did in the old days'. Gone is the Prince who looked forward, who experimented with electronica, who was such a classic-spewing genius that he could record Sign O The Times using the pre-programmed sounds on the Fairlight synth and still make it sound like nothing anyone had ever head. Now we have a Prince who looks back and reminds us at every interval that "this is real music, with real musicians".
It's a pity that Prince has such a negative view of technology and such an obsession with what he sees as authenticity. An electric guitar is, after all, a machine. But really it is Prince the artist who has the problem here and, honestly, that guy's creative peak was the extraordinary period between 1982 and 1987. In that short period Prince accomplished more than most artists do in a lifetime. His output has been estimated by scientists to be roughly equal to 1,348 BRIT schools.
The decline of Prince the artist did not affect Prince the performer, who remains a startling and awesome force on stage - James Brown, Michael Jackson and Jimmy Page packed into one little body. His charisma is such that he can pull of things that from another performer would be cheesy or sleazy and still seem like the coolest man on the planet. He's also the only Jehovah's Witness you'd be happy to open the door to.
His set at Hop Farm last night contained several of his greatest songs but left many more unplayed. There was no room for When Doves Cry, Seven, I Would Die 4 U, Pop life, Alphabet St, Diamonds and Pearls, My Name Is Prince, Thieves in the Temple, Gett Off, Sometimes it Snows in April or The Most Beautiful Girl in the World. Who else could leave that many great songs off the setlist and still deliver a show as good as last night's?
There were brilliant versions of Little Red Corvette, Kiss and Controversy as well as a take on Purple Rain that seemed to last for half the set but there were also lots of covers. I agree with my Telegraph colleague Lucy Jones that more Prince classics and fewer covers and funk workouts would have been more satisfying but I think it's the covers that drive Prince's enthusiasm. And more importantly the covers add an excitement and unpredictability that is missing from other nostalgia acts.
At the same time as Prince was playing at Hop Farm, a reformed Pulp were playing in Hyde Park. Much as I like Pulp, I'm not disappointed to have missed them. I saw them several times back in the days when Disco 2000 was a song about the future. Their setlist last night was basically the same as the ones I saw then. Of course they'll play Common People and Do You Remember the First Time? and Babies. How could they not?
One of the things I value most in a gig is the unpredictable - as you can probably guess from things I've written before. There can be no element of surprise in watching the reformed Pulp, just as their wasn't when Blur reformed two years ago. That's not to say that there is anything wrong with watching either but it's a comforting experience - like re-watching a favourite movie - rather than a thrilling one.
I could happily have watched another hour last night. Prince's genius as a performer is that he has managed to maintain an electrifying unpredictability in what is still in essence a nostalgia act.