The Endellion Quartet’s experience tells impressively in this collected edition not just of the regular Beethoven string quartets but also of variants plus the string quintets and fragments. In addition, this is the first recorded cycle to adopt the amendments suggested in Jonathan Del Mar’s scholarly Edition. I had never realised that the first version of Op 18 No 1, for example, is markedly different from the text we know. It is fascinating here to have both versions on the first of the 10 discs, with Misha Donat’s authoritative notes analysing the principal differences. It is also good to have Beethoven’s own neat arrangement of the Op 14 No 1 Piano Sonata. As for the fragments, none is specially valuable but they are all worth hearing, as are the String Quintets, Opp 4 and 29, and two fugues for string quintet.

The Endellions have always been an intense, sensitive group, and here their merits after 30 years are highlighted by the comparison in two pieces with the Artemis Quartet. Polished as the playing of the Artemis is, there is an extra refinement, of pointing of detail and in tempo choices, in the Endellion versions. For example, Op 18 No 4 has no regular slow movement, but whereas the Artemis treat the second movement as the substitute for a Scherzo, the Endellions follow the marking Andante scherzo with the lightest of pointing at a brisk speed, and treat the Minuet third movement marked Allegretto as the slow-movement substitute, all with telling effect.

Op 59 No 2 draws from the Endellions the most refined, dedicated playing in the visionary slow movement, whereas the Artemis are relatively earthbound, polished as they are. At every point the Endellions demonstrate their extra maturity. They consistently play with inner depth and dedication, and employ the widest dynamic range, with whispered pianissimos as intense as the biting fortissimos.

I haven’t compared this new set with those of rivals such as the Lindsays, but with perfect intonation and matching, this is a most valuable new issue, particularly with such a wonderful collection of bonus items. The recordings are also a model of balance and refinement.