Viktoria Mullova, Paolo Giacometti (****)/ Vilde Frang, Michail Lifits (*****)

Wigmore Hall, London

Ever since her escape from Soviet Russia at the height of the Cold War, the violinist Viktoria Mullova has stayed firmly in the public eye.

Initially this was thanks to the icy perfection of her playing, but her marriage to cellist Matthew Barley led to fame of a different sort as she embarked on a series of jazz and folk collaborations. Then she got into gut-string period-instrument performance, which is where she is now: bringing Paolo Giacometti with his fortepiano – rather than a Steinway - to join her for a Beethoven recital was a typically bold move.

The sound created by gut strings (plus a fortepiano) is as different from that of metal strings (plus a modern grand) as candlelight is from neon, and when Mullova and Giacometti launched into the ‘Sonata in A minor Opus 23’ one had to make an immediate aural adjustment. But this music sounded as though new, with the balance between the instruments permitting a light and flexible approach and allowing their respective timbres to blend beguilingly.

While Mullova’s pure line exuded cool authority, Giacometti played with the most subtle refinement, with the slow movement of the ‘Spring’ sonata expressing a tender collusion surely closer to what Beethoven intended than what we are used to today. There were moments – notably the resonant theme of the Andante in the ‘Kreutzer’ – when I would have preferred the heft of a Steinway, and some of the variations were unnecessarily hurried, but the hurtling violence of that sonata’s outer movements came at us with full force. This concert was a revelation.

The case for modern instruments was brilliantly made by the young virtuosi who took the stage the next day. The 24-year-old Norwegian violinist Vilde Frang – who looks as if she’s stepped out of a Pre-Raphaelite painting – has a line as clean and pure as Mullova’s. And in tandem with the Uzbek pianist Michail Lifits she gave an account of Mendelssohn’s ‘Sonata in F’ which was both full-blooded and finely nuanced, with Lifits delivering the whirlwind figurations of the finale at a speed which took the breath away. Lutoslawski’s ‘Partita for Violin and Piano’ calls several times for both players to improvise before simultaneously arriving at the same end-point, and they met this challenge effortlessly, before zapping us with three richly-coloured Hungarian Dances by Brahms.

This stunning performance can be heard again on Radio 3 on Saturday afternoon.