On Saturday morning, as well-adjusted people skipped happily off to parks, picnics and the like, I made my way to the ICA and descended into the darkness of the third of six of the weekend's 'live recording sessions' by industrial pioneers Throbbing Gristle. The midday setting was disorientating. Outside, tourists milled in the sunshine, snapping photos of soldiers practising for the Queen's birthday. Inside, our one-time Wreckers of Civilisation prepared to weave their dark magic(k).

31 years after their infamous 'Prostitution' show at the same venue reputedly shook Western civilisation to its foundations, a small band of ticket-holders were here to witness all four members of the band create their next album, an interpretation of husky-voiced chanteuse Nico's classic 1970 album "Desertshore".

It was as far from a live performance as you can get. Cosey Fanni Tutti, Peter 'Sleazy' Christopherson, Chris Carter, and Genesis P-Orridge – resplendent in blonde bob, and fluoro green/orange top hugging his surgically augmented breasts – had essentially transplanted their recording studio to the stage. Sleazy introduced proceedings, then they set to work – bickering, recording, playing back, re-taking, wandering about, joking with each other, and drinking cups of tea. If it sounds like watching paint dry, it is actually weirdly fascinating. Genesis is charismatic, laying down vocals in the booth at the side of the stage – during the recording of "Le Petit Chevalier", on which Nico's seven-year-old son originally sings, a disconcerting effect is created as he doomily rasps over the hesitant guide vocals.

At times, little happened. An extended electronic jam (with Gen sawing at a distorted electric violin) goes nowhere in a hurry, but that isn't really the point. The audience are flies on the wall as these musicians lay themselves brutally bare, devoid of image save their own creativity, and a velvet rope arranged ironically across the front of the stage.