The advance publicity for Florence Welch’s third album has made a great deal of its apparent differences from its predecessors. According to the singer herself, How Big How Blue How Beautiful is an album about heartbreak, concerned with “stripping down layers of things to hide behind: big sounds, big dresses, big metaphor”. Despite the presence of producer Markus Dravs – latterly the go-to guy for artists of a certain world-conquering, stadium-filling bent, including Coldplay, Arcade Fire and Mumford & Sons – listeners are primed to expect the epitome of understatement and restraint, the work of a “quiet person”.

Thus far, Welch has spent her career behaving as though understatement was something you should go out of your way to avoid contracting: everything from vocals to visuals is pitched at a level just shy of frenzied. It’s an approach that’s proved spectacularly successful – both her albums to date have gone platinum on both sides of the Atlantic, and commercial expectations here are high. “We will not be satisfied with anything but a No 1 release,” the president of her US record label recently told the New York Times, a remark which presumably wasn’t supposed to sound quite as weirdly menacing as it does: as it is, you somehow imagine him adding “or there will be consequences” and slowly drawing his finger across his throat.

It takes about 10 minutes for the listener to realise that reports of Welch’s new-found reserve might have been slightly over-egged. It’s at that point that the title track appears, bringing with it that legendary musical signifier of modest understatement, a 36-piece orchestra: strings saw dramatically, brass blares out, little bursts of woodwind scurry about, what appears to be a dulcimer and something that sounds like a celeste attempt to muscle in on the action. It’s understated only in the sense that she didn’t get someone in to let off a cannon like in the 1812 Overture. The sneaking suspicion that How Big How Blue How Beautiful perhaps isn’t going to be entirely as advertised is hard to avoid.

In fairness, there are a couple of moments where things are dialled down slightly. On her previous albums, she essayed everything from ballads to EDM fluff in a war-cry bellow, suggestive of furrowed brows and bulging veins. You got the distinct impression that if, for some reason, she was required to perform Lip Up Fatty by Bad Manners, she’d give that the full war-cry treatment as well. Here, however, Long and Lost features the hitherto-unimaginable sound of Welch singing softly: there are massed backing vocals, but they stay muted and distant, haloed in reverb. St Jude is more unassuming than you might expect a song starring the patron saint of lost causes and miraculous curer of King Abgar of Edessa to be: a delicate, harmonium-led ballad.

But their presence highlights the fact that elsewhere it’s all guns blazing: tribally thumping drums, distorted guitars grinding out garage-rock riffs, pianos banging out melodramatic chords, vocals multitracked into infinity, strings shimmering and lyrics in which Welch compares herself to both Persephone, daughter of Zeus and princess of the underworld, and faithless Old Testament hottie Delilah, as well as invoking Mother Earth and demanding to be turned into a tree. There are occasions on which heartbreak seems to have made her voice more histrionic than ever, as evidenced by What Kind of Man, a bug-eyed performance with lyrics to match: “You inspired a fire of devotion that lasted 20 years … Oh mercy, I implore.” “What kind of man,” she keeps demanding to know, “loves like THEEEEEEEES?” Occasionally you start sympathising with the man who loves like theeeeees. “You’re driving me away!” she roars on Queen of Peace, and you think: I’m not surprised, he’s probably worried about getting a perforated eardrum.

It’s an album that’s too overblown and daft for the songs to have the desired emotional impact: it’s never really intimate enough for the feelings Welch expresses to connect. Instead, it wobbles precariously along the line that separates the enjoyably OTT from the faintly exhausting. That it lands in the former rather than the latter category is down to something really prosaic lurking beneath the references to Greek mythology and the teeming sound. Welch, or someone in her songwriting team, is exceptionally good at writing polished, radio-ready melodies: hooks that dig in, strong enough to support the weight of everything that gets shovelled on to them. There’s something breezily unforced about the progress of the title track’s tune, or the way the chorus of Various Storms and Saints surges into life, an ease that undercuts the evident pains involved in the vocal and arrangement. What should be hard work to listen to just isn’t. How Big How Blue How Beautiful doesn’t sound much like the album suggested by its advance publicity, but what it does sound like is a hit: immaculately done pop songs dressed up in gaudy melodrama. There doesn’t seem much danger of the guy from her US record company being unsatisfied.