MUSIC / His papers are in order: Andrew Green talks to Robert Threlfall about his work on the recently completed Delius Collected Edition

Dud notes have always been a bit of a worry to Robert Threlfall. After a career spent supervising the production of fivers and tenners - security printing, they call it - the first decade of his retirement has been taken up spotting wrong notes amid the sharps, flats, crotchets and quavers in dozens of Delius scores. Now at last, thanks to his work as project coordinator, all 33 volumes of the Delius Collected Edition are available to those with pounds 1920 to wave around. Or buy them in ones and twos, if you please. Last night, at Stationers' Hall in London, the Delius Trust threw a dinner to mark Threlfall's achievement - ahead of schedule and to budget, at a final cost of around pounds 220,000.

The volumes were produced in cooperation with a variety of publishers - in many cases those who published works when they were in copyright. 'The Trust has put its own cash into the project to a greater and lesser extent depending on the size of the tasks involved,' says Threlfall. 'For example some works, like the Suite for Violin and Orchestra and the American Rhapsody, hadn't been published before, so the work started from scratch.'

Threlfall is used to having composers hovering at his elbow. In his spare time over the years he has written extensively on the likes of Mahler, Shostakovich, Mozart and Janacek. This time it has not just been Delius looking over his shoulder but the waspish, goat- bearded presence of Sir Thomas Beecham keeping him on the straight and narrow. The Collected Edition represents the Delius Trust's completion, at last, of one of the fundamental objectives set out in the will of the composer's wife Jelka, who died the year after her husband, in 1935.

Delius himself left no clear instructions about the creation of a Collected or published Beecham Edition - or even a Delius Trust, the latter in fact being a bone of contention after his death between Beecham and another close friend, the composer Henry Balfour Gardiner. Jelka's instruction to what is essentially the Jelka Delius Trust was to pursue 'the publication of a uniform edition of the whole body of the works of my late Husband,' under the general directive to 'obtain and faithfully observe the advice and opinion of Sir Thomas Beecham', the composer's friend and champion.

A number of his marked Delius scores, with their mass of thick blue pencillings indicating dynamic markings, hairpins, a few tempo indications and the odd technical instruction, were translated into just five volumes of the published Beecham Edition between the early Fifties and mid- Sixties. Large numbers of the marked scores never made it to the engraver's bench as for nigh- on 20 years after the conductor's death in 1963 the series dried up, Beecham's personal Delian archive consigned to a chubby blue trunk which threatened to become a large white elephant. 'The edition was put on hold partly because of copyright difficulties, partly cash . . . but essentially the Trust was concentrating on the urgent priority of promoting recording and performing - getting Delius heard,' says Threlfall.

When Threlfall took up his challenge in 1983 the remit was to return to Jelka Delius's strictures about Beecham. Accordingly the heart of the Collected Edition is the publication of all Beecham's marked scores, with due care taken to correct previous printing errors in the Beecham Edition (occasionally, as in the Florida Suite, surprisingly numerous) and sensitively to add new details of Beecham's performing practice which have come to light, including information from orchestral parts. But never an intended note of the originals altered. Of the scores untouched by Beecham, several (such as the Cello Concerto and Life's Dance) have been edited by Delius's celebrated amanuensis Eric Fenby. One score - the opera The Magic Fountain, previously unpublished - was prepared by Norman Del Mar, who played under Beecham. As for the half-dozen remaining scores, the decision was taken to publish them unedited.

Beecham's importance as a touchstone goes well beyond his interpretation and championing of Delius's music to the nature of the composer's manuscripts, in their neat, tiny hand. More than perhaps any other significant composer of modern times, he left performers few clues about what actually to do with the notes. 'He didn't approve of plastering scores with a mass of directions,' remembers Eric Fenby. 'He said the music itself held the key as to how it should be played. Not that he considered there was any one way it should go - he was satisfied if he detected a feeling for the music and could enjoy markedly different performances of, say, the Cello Concerto, by Barjansky and Beatrice Harrison. So yes, in a way it was a contradiction that he supported Beecham's performances and score markings as strongly as he did.'

The truth is, of course, that in Delius's lifetime several conductors took up his music enthusiastically, if not with Beecham's crusading zeal, and were on occasion fulsomely praised by the composer for their sense of his style. Hans Haym for years presented Delius's works in Germany before the Great War; Henry Wood gave first UK performances and Hamilton Harty is remembered as a particularly persuasive interpreter, recognised by the composer as such. 'Harty was marvellous with A Mass of Life,' says the baritone Roy Henderson. 'Beecham would treat you like one of the orchestra players - Harty worked with you.'

'Delius is too glibly identified with Beecham,' reckons Delius Trust archivist Lionel Carley. 'Yes, Beecham did have the sovereign approach - no question - but it's too simple just to say he led the way: others would have done so if he hadn't' To Sir Thomas Armstrong, Adviser Emeritus to the Trust and a prime mover in keeping the back-burner glowing under the Collected Edition project after Beecham's death, the contribution of Balfour Gardiner has been sorely underplayed. 'It's impossible to exaggerate his importance. He was a huge help to Delius in copying scores, preparing them for performance, proof-reading and so on. He asked for and got nothing tangible out of it, while Beecham benefited a great deal - the kudos, the beautiful performances . . .'

The rationale behind the Delius Trust's deference to Beecham is clear and comprehensible. 'We had a duty to carry out the provisions of Jelka Delius's will,' says Robert Threlfall, 'in the additional knowledge that Delius made it quite clear he regarded Beecham's performances as authoritative, telling others that Sir Thomas was editing his scores.' Few will be so churlish as to suggest the new Collected Edition is anything other than a thoroughly welcome arrival and an important achievement. But reservations exist. Violinist Tasmin Little, rapidly acquiring a reputation as a distinguished young Delian, is well aware of the interpretative googlies tossed up by the bare, spare original manuscripts.

'But the problem is that Beecham marked everything. The score gets somehow cluttered and you can feel too inhibited to let your imagination flow. I can think of places in the Violin Concerto where I feel just the opposite to Beecham. But obviously the new edition is a godsend to anyone wanting rapidly to get a sense of the style.'

'Beecham said the first word on Delius, not the last,' adds conductor Vernon Handley, a veteran interpreter of the composer's music. 'Sir Thomas adored the music, brought off many very, very beautiful performances in my experience . . . but I find Delius tighter in terms of structure than Beecham was good at - his sense of flow was the great asset, but the music isn't as free as it sounds, it needs more control. I don't mind having very few directions in the score - I think it's a strength.'

Such thoughts bring the nearest thing to a snort from the genial Robert Threlfall. 'Beecham's sole sentence in his Delius biography about interpretation is exactly about control: 'It is imperative to maintain a tight control over the motion of the melodic line: otherwise there may be created an unpleasant sense of lassitude or shapelessness.' You see?' Threlfall likewise refutes suggestions that the Collected Edition should have signified page by page exactly what was added to Delius's original scores. 'Practical musicians wouldn't ask that - putting in so many italics, brackets and so on would just have made the scores so much more difficult to read. Unedited Delius scores are, after all, still available for those who want them. Anyone is welcome to make their own edition.'