Star FillStar FillStar FillStar FillStar

There were more than a few muffled sniggers when Ellie Goulding mused in an interview that her third outing would be an "experiment", only then to reveal that her wild foray out of the box would be to record "a big pop album". Of course, despite the Hereford-born star's folk-tinged beginnings, she has always been considered a pop belle - and as chart-topping hit 'Burn' proved, she also has quite the talent for it.

But maybe what Ellie meant was not so much about a big shift in sound, but rather a step up in superstardom. This is the moment she goes from a singer-songwriter who does pop very well, to a fully-fledged popstar who has her eyes set firmly on a chart residency.

It would make sense for Goulding, then, to team up with the biggest names in the business. Enter the hit-maker responsible for Britney Spears, *NSYNC, Backstreet Boys and, more recently and definitely more aptly in these circumstances, Taylor Swift. Max Martin's golden touch has been responsible for more KO hits than Mohammad Ali. Add to the mix previous collaborator Greg Kurstin (Katy Perry, Sia) and Ryan Tedder (Adele, Beyoncé), and you've got an all-star team to rival The Avengers.

But do big names mean big songs? In the case of Delirium, it certainly hasn't hurt it. Fifty Shades single 'Love Me Like You Do' is the most eloquent pop effort to ever soundtrack BDSM, while its follow-up 'On My Mind' is a striding reggae-tinted retort that definitely isn't a response to Ed Sheeran's 'Don't'. Both prove that Martin's pop expertise fits nicely with the 28-year-old's singer-songwriter brain. Again on 'Codes', the hooks come thicker and faster than a fishing tournament, while new single 'Army' builds and builds into a glorious mountaintop chorus. They are easy on the ear, inoffensively catchy, but effortlessly executed.

Goulding's songwriting partnership with Greg Kurstin offers the more interesting moments though. 'Aftertaste' scales its chorus with stomping beats and drizzled electronics, while Ellie hopelessly admits: "I know there's nothing I can do to make you stay." 'Don't Panic' sits on a bed of vivacious xylophone trickles as she warns: "I've got big dreams baby, so don't you overcomplicate it." It feels like, although both are fizzier than a cocktail of sherbet lemon and 7 Up, when working with Kurstin her lyrics are cleverly exposed and blunt. It gives the easily digestible earworms some depth and bite.

Where the album comes unstuck, however, is in the lack of consistency - not in quality, but in tone. At a mammoth 16 tracks long for the standard edition (this is potentially the Peter Jackson director's cut of albums), it hops from the wistfully golden 'Something in the Way You Move' to the glitchy garage of 'Devotion'. Even for Ryan Tedder's turn, 'Keep on Dancin', the combination of windswept whistles and Major Lazer-styled honks are out of sorts with what we'd expect from their collaboration (albeit an album highlight).

But as ever, Goulding's distinctive smoky vocal is what manages to keep it all together. She uses it here to full effect (all gentle growls and climactic bursts), saving the hodge podge of styles and plastic gleam of the factory-assembled melodies from becoming unidentified chart fodder. Delirium is Ellie's big pop moment - both in scale and sound - and it's a stage that suits her nicely.