Few readers under 60 will be able to remember much about the Third Programme feature in which Deryck Cooke, great Wagnerian, BBC old-timer and Gramophone contributor, launched the grandest of his grands projets – the revivification of a tenth Mahler symphony. There are obvious parallels with Anthony Payne’s more recent efforts on behalf of unfinished Elgar and profound differences too. Belying his low-key presentation, Cooke’s dramatic revelation was that a continuous Mahlerian argument already existed on paper, needing only to be set free by a sympathetic editorial team. His own would take in the veteran émigré composer-conductor Berthold Goldschmidt and, subsequently, two budding composers, Colin and David Matthews. “I’d like to make clear at the start that the score I’ve prepared is in no sense a ‘completion’ of the symphony but only an orchestral realisation of what must be regarded as Mahler’s first, unrevised draft. But this first draft is more comprehensive than has hitherto been believed…with continuity from beginning to end, however tenuous in places.”

Alma, the composer’s widow, apparently was relying on the advice of Bruno Walter when she forbade further performances. Fortunately she was persuaded to think again, additional pages were found and the first public rendition of a full-length performing version took place in London’s Royal Albert Hall during the 1964 Proms season.

The process is recalled in detail in this well-produced three-disc set and aficionados may rank it alongside such sensational Testament retrievals as the Toscanini/Philharmonia Brahms cycle or the Keilberth/Bayreuth Ring. That said, it is as well to anticipate a voyage into treacherous waters. Whether navigated by the soft-grained Philharmonia in 1960 or the brighter-toned LSO, there are plenty of rough moments. The necessarily incomplete studio rendering, including announcements as broadcast, moves more swiftly than the live account, preserving noises off and concluding applause. Both contain details later amended or corrected so that listeners unfamiliar with, say, Eugene Ormandy’s early recording (Sony, 6/66R) are likely to be brought up short. All of which may or may not matter to you given the obvious fervour of the music-making. What it must have been to experience the finale’s flute melody for the first time outside a BBC studio! Goldschmidt gives this exquisite moment all the time in the world.

It is a sad irony that Cooke, like Mahler himself, died young, leaving unfinished projects of his own, but he is well remembered here. The tapes, from whatever source, would appear to have been tactfully reprocessed to open out the mono sound and eliminate any awkward gaps in continuity. As demonstrated by the lively correspondence in last February’s Gramophone, not everyone has been seduced by the notion of a performable Tenth. Colin Matthews’s indispensable booklet-notes slip in a cautionary anecdote: “On the only occasion that Cooke met Otto Klemperer all that the conductor said to him was ‘I do the Adagio.’” Strongly recommended.