WHETHER OR not the Brodskys really are set on becoming the British counterpart to the Kronos Quartet (and if so, they'll have to do something about those waistcoats first), their performance of George Crumb's Black Angels certainly made it look like it. It was a broadcast of this 1970 quartet by the American composer that led David Harrington to form what became Kronos. "One night I turned on the radio and heard something wild, something scary. It seemed like a musical response to the Vietnam war. I didn't even know it was quartet music at first, but it was a magnetic experience," Harrington said.

WHETHER OR not the Brodskys really are set on becoming the British counterpart to the Kronos Quartet (and if so, they'll have to do something about those waistcoats first), their performance of George Crumb's Black Angels certainly made it look like it. It was a broadcast of this 1970 quartet by the American composer that led David Harrington to form what became Kronos. "One night I turned on the radio and heard something wild, something scary. It seemed like a musical response to the Vietnam war. I didn't even know it was quartet music at first, but it was a magnetic experience," Harrington said.

It's certainly a strange experience, comparable to Martin Sheen's journey up-river in Apocalypse Now. Subtitled "Thirteen Images from the Dark Land", Black Angels both deconstructs and enlarges the normal means of expression of the string- quartet form. The players are required to chant, to count in various languages, as well as bang gongs, shake maracas, bow wine glasses full of water, play their instruments backwards and obtain unusual strumming effects by wearing thimbles on their fingers. Everything is also amplified with a disquieting reverb in order to produce - as Crumb's notes have it - "a highly surrealistic effect". I won't even bother telling you about the numerology.

The Brodskys approached this defiantly loony-tune of a score with an emphatically British stiff upper-lip, carrying out its instructions to the letter. But whether because of or in spite of Crumb's wilful absurdity, Black Angels was a knockout, its 20-minute duration proving both challenging and engaging for players and listeners alike.

One of the most impressive aspects of a superbly handled reading was the Brodskys' impeccably selfless performance style. It may be because of their emblematically British reserve, but unlike Kronos, you somehow feel that you can trust them not to over-egg the pudding, however outlandish the ingredients. As a result, what Black Angels might have lost of its original, Vietnam war-era righteous indignation, was more than made up for by the dispassionate but nevertheless intense drama provided by the quartet's strait-laced adherence to the score.

The first half of this BBC Celebrity Series concert featured Stravinsky's brief but beautiful Concertino of 1920; the String Quartet No 8 by Peter Sculthorpe; Metro Chabacano by the Mexican composer Javier Alvarez; and the special commission, Pawel Szymanski's Five Pieces for String Quartet.

The Alvarez - which was originally arranged for quartet to accompany an art installation in a Mexico City subway station - was excellent: rich, pliant, and proudly Latin. In contrast, the Szymanski was a real teaser, requiring the players to jump through a series of mannerist hoops that tested their skills to the limit.

It was good, too, but the relief you felt at the end was comparable to having a large weight lifted off your chest. Throughout, the Brodskys were brilliant. They can't hope to emulate the Kronos Quartet, though: they're just too nice.