Pet Shop Boys, Tower Of London, London<br></br> Pharrell Williams, Hyde Park, London

Let's party like it's 1967

We're sat in what used to be the moat of the Tower of London. Four hundred years ago, we'd have been underwater and Neil Tennant would have been underground, clapped in irons. They didn't approve of his sort in those days. Even 40 years ago, if he wasn't sufficiently discreet about his peccadilloes, he might have found himself languishing in some dungeon. Times have changed and the positives self-evidently outweigh the negatives. On the other hand...

Before the last American election, Marilyn Manson opined that it would be a good thing if Bush won, because "art thrives under repressive regimes". I don't suppose he actually meant he wanted Dubya to win, any more than I actually mean that I want to repeal the Sexual Offences Act of 1967. But it does raise an interesting point.

When they're openly celebratory, Pet Shop Boys are at their weakest. Their finest moments are all about the closet. While Tennant and Chris Lowe have always been clever enough to leave room for a "straight" interpretation, the quiet pain of English sexual repression is their forte. For two decades, they have made coded meaning into an art form. And those who get it are not solely lesbians and gays. If the record sales don't already tell you that, then tonight's crowd (comprising far more than merely the fey faithful) must.

It's all very middle-class, at least inside the grounds, where swathes of seats have been snapped up for corporate hospitality. The Tower of London Music Festival comes with a "Picnic Drop-Off Point" (whatever that is) and, while I'm no lover of mud, sweat and beers, there seems something profoundly wrong about seeing someone carrying a Waitrose hamper and a rolled-up blanket to a gig.

All around the perimeter wall, however, hundreds of passers-by peer over for a free view. It's unclear how much they can hear over the questionable PA system (I'm in Block A, and with the booming bass and low-level vocals, it takes me a verse to recognise "Suburbia"), but if their eyesight's good and their hearing's better, they're in for a treat.

When Neil and Chris have got "Psychological" out of the way, Tennant says "OK, let's have some fun". They're as good as their word. PSB may have a new album to plug, the wonderful Fundamental, but - aside from "I'm With Stupid" and the exuberant "Sodom and Gomorrah Show" - they don't let it get in the way of a proper Greatest Hits party. Interrupted only by an acoustic interlude ("Home and Dry" and "Before"), it's thumping electronic pop music all the way: "Left to My Own Devices", "West End Girls", "Opportunities", "It's a Sin", and the triptych of Hi-NRG cover versions: "Always On My Mind", "Where the Streets Have No Name/Can't Take My Eyes Off You", and an inevitable encore of "Go West".

The lavish stage show matches the music. At one point, flanked by super-camp military police, Tennant dons a navy admiral uniform, with more medals than Idi Amin. At other times, he's surrounded by gold lamé cowboys, breakdancers, and hats of various sizes, including a stetson which takes four people to hoist (amid Spinal Tap scenes backstage), and a top hat which sprouts legs and starts to dance. It's all played out in front of a mesh apparatus which doubles as a projection screen (the twitching net curtains for "Suburbia" are a touch of genius) and a series of compartments for the hoofers to hide inside and shadow-dance. Alternatively, you might call them closets.

What's your favourite Curb Your Enthusiasm episode? For me, it's the one where Larry makes an innocuous remark about Wanda's rear end, leading his wife Cheryl to conclude that he has an ass fetish. "It's all unravelling now", she accuses. "Nothing's unravelling," he protests, "nothing's unravelling!"

Whenever I see Pharrell Williams (below), I think of that scene. The first clue was N*E*R*D's "She Wants To Move", specifically the arresting line "Her ass is a spaceship I want to ride". Then there's his recent single, "Angel", which began with the words "She's got an ass like a loaf of bread/You want a slice".

Psychologists would have a field day. Williams watches the opening credits of Star Trek, he sees an ass. Williams picks up some Warburton's on his weekly grocery shop, he sees another ass. Something's unravelling. Pharrell is emerging as pop's most prominent booty lover since Sir Mixalot. Perhaps the reason he's disappointed with Hyde Park's reaction to his first British solo show, "pretty girls" notwithstanding, is that we aren't mooning at him in unison.

It doesn't help that it's the ridiculously early hour 6pm, and most people have rushed straight from work and haven't yet had the chance to neck a £4.50 cider. Pharrell's failure to engage with the crowd is, however, mostly nobody's fault but his own.

Don't get me wrong. I've seen this man, within the umbrella of N*E*R*D, perform some of the greatest shows I've seen from anyone. As an auteur and an innovator, he's this decade's equivalent of Prince (capable of anything from mindblowing psychedelic soul to minimalist bleep-pop so beautiful you could cry), and as a songwriter and producer, he's this decade's Nile Rodgers. He's got it all. Dr Dre may be his nearest current rival in production terms, but Dre is fat, ugly, and can't rap for toffee, let alone sing. Pharrell, however, has a voice like Curtis Mayfield, he's skinny, and - regardless of the self-inflicted handicap of wearing a multicoloured wicket-keeper hat and paddling shorts - he's one handsome sonofabitch.

None of which explains why he's slightly narky today, berating the crowd for not making enough noise. When he hits the heights ("Drop it Like it's Hot", with British beatboxer Killa Kela, is jawdropping, and the a capella intro to "Frontin'" is sublime) you can understand his frustration. When he doesn't (tunelessly repeating the chorus to "Hot in Herre" 32 times simply will not do), you can't.

Remembering why he's really here, he reminds us that his long-awaited, much-postponed album will be released on 25 July, "and it's really coming out this time."

Then we'll see something unravelling.

s.price@independent.co.uk