“Newly revised and corrected” is how Artaria proudly announced its 1801 edition of these quartets. Exciting? Not for all scholars today. “The editorial approach is heavy-handed, transforming Haydn’s highly articulated style by the addition of ‘convenient’ slurred bowings and numerous extra dynamic markings”, protests Simon Rowland-Jones (Edition Peters). Poor old Haydn; he had personally made the changes.

The London Haydn Quartet, playing period instruments, accept them unreservedly. As may have Donald Tovey, who said, “Not even Op 76 is, on its own plane, so uniformly weighty and so varied in substance as Op 20.” Now an ensemble, unique in collective insight, in tempo-management, articulation of melodic design and assessment of harmonic weight, unfolds the substance. Mostly unconventionally. The first movement of No 3 might jolt, nowhere near Allegro con spirito. The phrases slowed down are dislocated – and disturbing. Passionate fervour dominates the C minor Capriccio of No 2, warmed by the lyrically moving E flat middle section. Add strange intimations of a threnody in the Minuet of No 5, the adroit zip of the Presto scherzando in No 4, the soft undertones in the fugal finales, sombre in No 5, bright in No 6, and there is simply nothing to support Rowland-Jones’s bewildering assertion that “a noticeable lack of character and rhythmic vitality results from following Artaria’s readings”.

Noticeable instead is the singularity of readings from artists who stake a claim on Artaria’s edition; and ignoring preconceived notions courageously accept responsibility for provocative interpretations – of enthralling magnitude.