‘4’ captures Diagonal in full creative flow and with a new twist to their sound as they incorporate elements of space rock, kosmische and post rock to bolster their well-established progressive rock roots. That adage of waiting ages for a bus and two or more come along at the same time seems applicable to their recent productivity. Returning only two years after the release of their previous LP 'Arc', this is a notable break from tradition, having left five and seven year gaps before the previous two. And after much deliberation, the band settled on following in the footsteps of Soft Machine and Led Zeppelin in naming the album after its chronological appearance.

Less is more’ is somewhat of a cliché but just ask Diagonal whether that rings true. Seven years on from 2012’s The Second Mechanism – the group’s second LP following their eponymous debut – they return as suddenly as they seemed to disappear, with arguably their finest effort to-date, Arc. It’s a record that maintains their effortlessly chameleonic shifts through Canterbury scene-indebted progressive rock, pulsing motorik and the spaced-out jazz expression; but where it really thrives is in its sense of spontaneity, imbibed from the quick and organic way that it came about.