Sofar – Songs From A Room – sets up free, intimate and unplugged gigs by emerging artists. A key added element of secrecy comes from the fact that the venue is revealed only a couple of hours before the show. Invitations are sent out to those who sign up to a mailing list.

“It’s growing faster than we ever imagined. In just three years we’ve grown to over 60 gigs a month across 70 cities,” said Offer. “We pick acts from every genre, so you never know if you’ll get an indie band, a beat boxer or even an opera singer.” For the guests the aim is to catch a band early in its career. “Bastille have played a couple of times, the National played at an event in Washington DC and the Staves played in Belsize Park a couple of years ago.”

Sofar Sounds now hosts shows from Amsterdam to Mumbai. Even small domestic spaces fit the bill and anyone keen to host a show can nominate their own lounge. On Friday night, the indie trio and Island Records signing We Were Evergreen played to 75 people in an arty flat in Paris. Another 350 people applied for a ticket but could not make it in.

The London craze for homely gigs has started an international “pop-up wave of events”, now encompassing, cinema, music and food. Operating on a similar basis is the company Secret Concerts, which works in collaboration with the recording label UntiedArtists. Like Sofar, they ask for donations from their guests and went into business, they say, because: “The most satisfying gigs are those where an intimate environment, a committed audience and a great performance combine to create a charged atmosphere.”