Rachel Zeffira, Union Chapel, London

You’ve got to hand it to God’s builders: reverential silence does work really well in a church. There’s a moment tonight - during a cover of ‘Because’ by The Beatles - where the wail of a siren cuts in from the outside and you realise just how quiet it is in here.

Quietly and beatifically calm we sit, gazing pulpit-ward with a strange expression of satisfaction. It is a performance which acts as a soothing balm applied to the psychological wounds inflicted by a troubled world, hypnotic and relaxing. But not just hypnotic and relaxing, for if those were the key elements of live musical performance then Larry the Blue Whale would have sold a shit load more albums than he’s currently managed.

More important are actual songs, and Zeffira definitely has those. Although, they are a bit weird. There’s a strange parallel you can draw with the venue: Union Chapel is a historical building that is now being put to a more modern use. Zeffira is taking the historic toolkit of a classical arranger and assembling songs with a more modern spin.

So what you have is numbers which are nominally quite poppy, in length, structure and subject matter (love; longing; loss; longing for lost love) dressed up in accoutrements that seem somewhat older. The mix gives rise to some fantastic moments. The baroque motions of ‘Letters From Tokyo (Sayonora)’ make it sound renaissance era; the stark defiance is pure ‘I Will Survive’.

‘Here On In’ manages to be gothic and eerie while adopting the same frantic fairground organ that made Arthur Brown’s ‘Fire’ seem totally unhinged, while ‘Break The Spell’ does anything but. The pace-quickening beat surrounded by the gentle caress of the strings and a chorus which swells skyward upon washes of cymbal and serpentine oboe to form into a motorik vehicle with cotton wool for wheels.

What’s perhaps even more remarkable is that all of this done with a fever and tonsillitis. Which must be a hell of a handicap for someone whose uses their classically trained voice in such a precise fashion. A bit like Liam Gallagher attempting to do a gig with a sprained ego.

There are occasions when the illness does seem to have had an effect, but in fact the more noticeable consequences - the way the vocals swoop precariously close to cracking (on the opening The Deserters) or the slightly breathy, slightly stilted phrasing of Front Door - actually kind of suit. They add an emotional weight, a sense of bitter experience to the elegiac wafts and the lovelorn laments that helps make them less sweet and more spooky than on record.

It is a wonderful thing to witness. A happy alignment of artist, venue and occasion which comes together to create something properly special. Fragile, beautiful and more than a little bit strange.