Britney Spears - Femme Fatale (Japan Deluxe Edition) (2011)

You don't want to sound like you're wishing the woman ill, but there's no doubt Britney Spears made her best album when she was at her worst. It wasn't merely that the various producers of 2007's Blackout – its recording somehow slotted into a pressing schedule of visits to rehab, head-shaving and being carried out of her own home strapped to a gurney while the world's media circled overheard in helicopters – took her apparently imminent demise as an excuse to try anything they fancied (in Freakshow, it contained possibly the first mainstream pop track to show the influence of dubstep); it was that Spears finally appeared to reveal something of her personality. Admittedly, said personality seemed pretty odd – the snarling Piece of Me claimed her ongoing woes were the result of a global media conspiracy to besmirch working mothers – but, for the listener at least, Spears's problems offered their own reward. Previously, she had seemed to be a weird absence at the centre of her own records: however great her singles were – and at their best, as on Toxic or … Baby One More Time, it's hard to think of any contemporary pop music that was better – it was a bit tricky to work out what the singer actually brought to the party, beyond a nasal voice so emotionally unengaged it made even Kylie's what-is-this-"kissing"-Captain-Kirk? approach to vocals sound like Janis Joplin doing Ball and Chain at Monterey.

You could argue that none of this matters: all manufactured pop stars are at the mercy of their songwriters and producers, and no one buys their records for their personality or in the vain hope of hearing someone wailing away like Janis Joplin. Certainly, 2008's normal-service-has-been-resumed Circus, on which the void returned in no uncertain terms, sold substantially better than its livelier predecessor. However, Femme Fatale arrives in a world where Lady Gaga is setting pop's agenda. Whatever else you might make of Lady Gaga – and if you suggested the supposedly nonpareil genius of her music tends to be a little overstated, you might have a point – you'd be hard pushed to argue that a woman who turns up at the Grammys in a giant plastic egg, then performs her new single wearing flesh-coloured protuberances on her face lacks character.

But if the pop personality stakes have been raised, no one seems to have told Britney Spears. On Femme Fatale, her voice is as anonymous as ever, a state of affairs amplified by the lavishing of Auto-Tune. She does what pop stars invariably do in lieu of having a detectable character of their own: goes on and on about sex, a topic that becomes a bit tiresome if you're stuck with a vocalist who sings the line "you can be my fuck tonight" with all the erotic charge of someone suggesting you put the recycling bin out. After a while, you get the feeling the lyricists just gave up trying in the face of her indifference: "You got me kind of hot … Steaming like a pot full of vegetables," she sings, which somehow makes you think not of thrillingly sweaty congress but the smell of boiled cabbage. You listen to Spears flatly intone the flatly hopeless simile "Like telepathy, I know what you're thinking," and conclude this might be why people go so nuts about Lady Gaga: she's clearly making an effort in an area where most of her competitors don't appear to be making an effort at all.

That's not to say that Femme Fatale is a failure. At its best, the producers come to the rescue, something they noticeably failed to do on Circus, an album that reiterated its everything's-normal-there's-nothing-to-see-here message by sticking with default pop settings rather than taking risks. While there's certainly some unremarkable stuff on offer, notably Seal It With a Kiss and I Wanna Go, it's outnumbered by tracks on which the music is genuinely exciting. The dubstep influence returns on both Hold It Against Me – featuring a thrilling, grinding breakdown amid the distorted beats and rave synths – and Inside Out, which lurches along on the genre's patent half-speed rhythm. The backing against which Trip to Your Heart's sugary melody is set is fantastic, a weirdly scattered burst of electronic buzzes and clicks. Likewise How I Roll, a nursery-rhyme tune given a sheen of weirdness by a sparse arrangement of gasps and ping-ponging effects.

Even in a changed pop climate that shows up its shortcomings more clearly than ever, you'd be hard-pushed to call Femme Fatale anything other than a success, albeit a rather old-fashioned one: despite rather than because of the woman whose name is on its cover. At its best, it sounds like a party, with a cutting-edge pop soundtrack. The question of precisely what Britney Spears brings to said party remains as imponderable as ever.