The first time I saw the precociously talented First Aid Kit was at Pure Groove (RIP) in early 2009. Back then, Johanna was only 18 and Klara 16, but even then, it was obvious that the sisters Söderberg had the potential to evolve into something special. Almost half a decade on, and the girls are somewhat taller, infinitely more confident, and performing for significantly larger audiences. But that initial charm, that genuine glee and love of music, is still impressed on everything they do.

What’s immediately striking is how assured they are on stage. Whilst many practitioners of their winsome brand of folk tend to be quiet, reserved types, Johanna and Klara are natural performers; witty, charismatic and seemingly unflappable. At one point Klara fumbles a line but recovers with a panache most performers would struggle to equal; later, an unanticipated interruption by the bells of St Mary le Strand are dealt with by improvising around the peals.

Yet even their poise and professionalism pales in comparison to the delightful heartiness of their voices; not prissy and oh-so-delicate, nor glacial or ice-maidenish, but full of texture and unusual warmness. Combined with some rich and well-judged arrangements, their sometimes overly earnest songwriting is infused with a depth and character that isn’t always apparent in their recorded works. Even a non-folkie like myself cannot help but be moved.

The most memorable moments are where the sisters ditch the restraint and let their passion truly shine through. Fan favourite ‘Emmylou’ is delivered with special enthusiasm and flair, and the climax to the set, with Johanna hammering on her keys with rock star abandon to the bassline of ‘Seven Nation Army’ with two hands and a foot reflects a wildness and effervescence that one hopes might be channelled into their future works.

It’s an impressive performance by any standard, but for an act of such youth it’s quite astonishing. One suspects that in another half-decade, we’ll be seeing them in venues much bigger than this. It’d certainly be well deserved.

Photograph taken at Shepherd’s Bush Empire, summer 2012 by Sara Amroussi-Gilissen