Circus is being touted as a sequel to last year's Blackout, the freaky, fantastic "robopop" album that became the unexpected highlight of Britney Spears's recording career. The main difference? This time Spears is in control, a message that's spelled out when she declares "I'm like the ringleader, I call the shots" on the second track. There's a lot less vocal trickery here too - presumably because the resurgent star doesn't need it - and at one point Spears is even introduced as the "Queen of Pop", a title which might preclude future offers of collaboration from a certain M. Ciccone.

However, this isn't to say that the intriguing weirdness of Blackout has entirely been erased. As befits an album whose back cover shows a child dressed as a clown handing Spears a birthday cake, Circus features several songs you just wouldn't expect from an 80-million selling pop superstar. 'Blur', which is best described as a "hangover ballad", sees Spears wake up, moan that the lights are "way too f***ing bright" and then realise she doesn't know what - or who - she did last night. Then there's 'If You Seek Amy', which not only conjures up images of Spears stalking Amy Winehouse, but also gets her to chant the line: "All the boys and all the girls are begging to if you seek Amy". If you don't get it, you're not saying it fast enough.

Both, however, are trumped by the utterly bizarre 'Mmm Papi', which seems to reference the star's now extinguished relationship with paparazzo Adnan Ghalib. One of three tracks on Circus co-written by Spears, it finds her fantasising about being whisked away from the throng surrounding her by a man in a fast car whom she refers to as either "mmm papi" or "mmm papa". "I'm mami and that makes you papi... and that makes us lovey," she coos over the outro. Britney Spears, in case you were wondering, turned 27 the day after Circus was released.

Sadly, the other notable difference between Circus and Blackout is that there's more filler here. No fewer than nine different producers or production teams worked on this album - including Max Martin, Blackout stalwart Nate 'Danja' Hills and Swedish pop whizzes Bloodshy & Avant - and it's hard to see how they couldn't come up with something better than the virtually melody-free 'Mannequin' or the tepid electrofunk of 'Lace and Leather'. Then there are the ballads, something which Blackout shrewdly avoided. The teary-eyed 'Out From Under' is actually a pretty decent song, but it doesn't fit on this album, while 'My Baby' is almost unbearably icky.

Thankfully, Circus is saved by a handful of songs that almost match the brilliance of Blackout's 'Piece Of Me'. The bolshy rave/glam hybrid of 'If U Seek Amy', the brilliantly bombastic title track, the stadium pop romp of 'Amnesia', the drill-like 'Womanizer' and the startling 'Kill The Lights' are among the best moments you'll hear on a pop album this year. These tracks alone are enough to bring Britney Spears - a woman who seemed bleary, bloated and almost beyond help barely six months ago - tantalisingly close to a fairly audacious comeback.