There’s something resoundingly old-fashioned about Portishead. They refuse to play the game – three albums in 20 years is not the usual stuff of the pop business – but yet they have the heft to warrant these positions at the sharp end of a festival bill.

What they also have is a sound which has never gone out of fashion. As the witching hour approaches, their dramatic, emotional sounds of black and blue hues bewitch and entrance. Tracks from their debut album Dummy, 20 years old this week, still sound remarkably fresh and agile, while Machine Gun from their most recent album Third packs one hell of a punch, all grating noise and great blasts of menace.

At the heart of this carefully orchestrated maelstorm is Beth Gibbons, the woman singing the torch songs at the deserted bar at the end of the world. In between the snap and the hiss, the cackle and crackle of the music, Gibbons turns sighs and laments into grace notes of magnificent, mighty import. Truly a band for all times.

In three words: Bristol cream deluxe