First Aid Kit, Somerset House, London

This year’s Summer Series was kicked off by bass-wobbling crooner Alex Clare and will conclude with ever-vibrant dance heavyweights Basement Jaxx, but tonight’s harmony-honeyed folk is perhaps the most in keeping with Somerset House’s wondrous stony courtyard. Sure, the West End’s cultural bull’s eye has and will play host to more rambunctious line-ups during its seasonal stint, but the tranquil setting, hot night air and cathartic soundtrack are the perfect antidote to a day usually associated with post-weekend doom.

First, quivering troubadour Jo Rose dishes up the sort of quaint, Night Beds-ish torch songs that sooth any lingering traces of start-of-the-working-week blues. The Anglo-American is even joined by half of the headline act, Klara Söderberg, for an untitled new song; a sleepy-eyed, Smog-ish lament that silences the hubbub and revels in steadily-building captivation. However, LA’s Milo Greene are a far less subdued prospect; they pump their delicate-on-record cinematic pop to stadium-shooting sonic heights in the flesh, albeit by way of some painstakingly rehearsed instrument-exchanging. Nevertheless, cuts from their eponymous debut album sound grandiose in the neo-classical setting during their support slot; ‘What’s The Matter’ thumps along, all tribal beats and calypso-tinged rhythms, before the gang vocals of a rather souped up ‘1975’ shudder towards an anthemic climax. Although, it’s the heart-weary ‘Cutty Love’ - which sounds like Fleet Foxes with added vim - that best impresses.

Of course, live, Swedish sisters First Aid Kit aren’t usually matched in terms of sheer aural perfection and tonight is no different. They open with the delicately seductive ‘Blue’, its breezy melody proving the ideal companion for a stage illuminated by tiny twinkling lights. Then, as the sun slowly heads for bed, the bewitching storytelling of ‘This Old Routine’ bestows a moment of majesty out of a subject matter that fixates on the mundane; the siblings’ rich harmonies melding to form a shiver-inducing coo. Although, not entirely reliant on last year’s outstanding release ‘The Lion’s Roar’, they digress; a clattering take on Bob Dylan’s ‘One More Cup of Coffee (Valley Below)’ proving the most fitting of a trilogy of covers, which also sees faithful takes on Patti Smith and Simon & Garfunkel. Then, with the wailing pedal steel and drums absent, the duo stand alone for a rare and endearingly rusty rendition of ‘Ghost Town’; it’s the highlight and even the clock thinks so, its timely, appreciative chimes triggering a one-in-a-million call and response with Klara’s finger-plucked acoustic.

‘Londaaaaan! Do you want more?’, cries a bare-footed Johanna Söderberg from behind her keys on their crowd-urged return, before Jo Rose emerges to fill a Conor Oberst-shaped hole for closer ‘King of the World’. Assured, classy and utterly mesmerising, it is final testament to two still bafflingly-young songwriters, who lest we forget still have their best ahead of them.