Antony And The Johnsons/Florence And The Machine/VV BROWN, Royal Albert Hall, London

Usually the support band has to make do with the chosen stage set-up of the headlining act, but in tonight's imaginatively concocted line up by the Teenage Cancer Trust, each of the three performers has almost equal stage time – and equally large and eccentric personas.

First up is the sassy soulstress VV Brown, whose relentlessly upbeat doo-wop soul songs are a suitable opener for rousing the crowd."Come on, let's have a little fun" she chirps, beginning with a Super Mario Brothers sample and launching into "Crying Blood". Dressed in a slinky sequinned tunic dress, with piano keys for a hem, she shakes a tambourine to the backdrop of a short film of couples swing dancing.

For the arrival of Florence and the Machine, who won this year's Brits Critics' Choice, taking the crown from last year's winner, Adele, the stage has been filled with an elaborate array of bird cages and pink flowers. All flame-coloured hair tumbling over a striking black gown reaching well below her feet, with feathers covering her shoulders, Florence looks like an ethereal elf queen, the newest addition to the school of inventive and theatrical singers Bjork, Goldfrapp and Natasha Khan of Bat for Lashes.

But it is her voice which demands attention. Her songs benefit from the acoustics of the Royal Albert Hall. Beginning with "Lungs" she fills the cavernous hall with her powerful voice and the instrumentation is crystal clear. But springing from the glorious harp glissandos are Florence's body-part-referencing and often violent lyrics – as in single "Kiss with a Fist" ("not about domestic violence" she posted on her MySpace page).

In "Girl with one Eye" "cut your little heart out" she screams as she throws back her hair wildly. Strange, then, when later she abandons the mic, approaching the stage lip, her voice tiny, and gets the giggles. With not even her debut album out yet, Florence won an army of new fans.

Antony Hegarty gets the welcome of a hero; it's clear it is he is the crowd wants to see. Lights dim, there is heightened expectation as the Johnsons form a cluster next to the piano behind which Hegarty is perched. From the moment they start a set which focuses on their newest album The Crying Light, the crowd falls into a hushed reverence. When someone dares to talk mid-song, eyes glare.

Hegarty's between-song chatter is welcome, though. His unexpected admission, "sorry I'm a bit squeaky – they gave us too many custards and puddings backstage", gets affectionate ripples of laughter. His tender explanations of a handful of songs shed light on the character within the complex songs, his being an outsider child looking to find his inner peace (The Crying Light). Less welcome is the interruption to "Another World", where after the steady violins have set the mood, he breaks the intense moment to explain his fears for the environment and the grieving process which inspired the track. As the song moves through grief to healing, dissonant violins find harmony.

Hegarty's "transgender" voice rises and falls in the hall like a beautiful other-worldy instrument and there are moments of real emotion. His emotively sung chorus to "You Are My Sister" from his 2005 Mercury Award winning album I Am a Bird Now has tears welling in your eyes, as do the violin, guitars and warm flourishes of recorder from the multi-instrumentalist Johnsons. "Aeon", too, has one of his many touching lyrics: "All the stars, your eyes. Raining just for me".

When the 6ft 4in Hegarty rises to a standing ovation and tells his audience to "take care", you can't help believing he means it.