Few people, you might think, would attempt to finish an incomplete work by one of the world’s greatest artists or writers. In fact, it seems almost inconceivable that anyone would have the effrontery to top up a Tolstoy novel, say, or a painting by Picasso. Yet over the past century the world of classical music has seen a plethora of attempts to do exactly this.

There have been completions of Mahler’s Tenth Symphony, Elgar’s Third; even – from hobbling together a few sketches and ideas – a Beethoven’s Tenth. And what seems extraordinary is that these completions, though they result all too often in ignominious oblivion, keep coming. On Tuesday the Orchestra of the Age of Enlightenment will be performing yet another attempt at a finished Unfinished Symphony by Schubert – completed, this time, by the Russian Anton Safranov.

Whatever audiences or critics make of them, performance of these alternative versions can feel distinctly odd for a player. There is often an amateurish, juvenile flavour to them. Rarely do they feel like an authentic performance given for authentic reasons. And then there are the bewildering semantics. For, in this context at least, “completion” covers the whole gamut of renovation work – from daubing on Polyfilla to building a major extension.

So perhaps it is predictable that the less that survives from an original score, the more unconvincing seem the results. Any attempt at Beethoven’s Tenth, for example – built up from a few meagre original sketches – has provoked particularly scathing reviews from musicians and audiences alike. And previous completed versions of Schubert’s Eighth Symphony (the Unfinished), which require the wholesale invention of two further movements, have not fared much better.

It’s true that Anthony Payne, who “completed” Elgar’s Third in 1997, scored both a critical and popular success. But the resulting symphony worked more as a composition by Payne than as one by Elgar – to say, as he did, that the work was “pure Elgar” was disingenuous, or piffle, as the Times said at the time.

So if the building-from-scratch completions neither convince nor endure, then what is their purpose? We simply patronise our audiences if we assume that they cannot tolerate a symphony without four movements. They are unlikely to be written for the fulfilment of the players – rare is the orchestral musician unable to drink his postconcert pint in peace unless he has played four solid movements. In fact, it’s often the uncelebrated instrumentalists’ ability to unify a patchwork completion with the requisite style of the original composer that gives the thing any authenticity in the first place.

So it is tempting to see these completions as X Factor-style opportunities for musicologists to strut their stuff, perhaps, or as classical music’s equivalent to plastic surgery and air-brushing fakery. And it all seems suspiciously easy, capitalising on works already made famous. Yet in the meantime, the lesser-known, more obscure works of the original composers often remain unexplored.

It is the tacit assumptions made here that are galling, the dissembling – a name taken in vain – that jars. Elgar himself expressly forbade a completion of the Third. Schubert, who lived for another six years after he had written the Unfinished’s two movements, was evidently not in a hurry to complete an Eighth Symphony. Nevertheless, graveyard silence is taken for assent, and licence is given for others to “complete” works, of which, in many cases, little has even been started.

Most classical musicians that I know admire genuine and heartfelt talent, just as they respect musical originality and spontaneity. But they are also aware that a high level of skill-based precision is required to best convey a composer’s intentions. And all too often, it seems, such “completions” fall lamentably between these two stools. They possess neither the immediacy of great talent, nor do they accurately impart another’s voice.

There is, meanwhile, plenty of outstanding and innovative musical talent in this country that risks being neglected altogether. So perhaps it is time we said no to these cosmetic surgery jobs; such rejuvenations are only skin-deep, after all. The face of classical music would be far better served, surely, by supporting those who create of themselves for today.

Philippa Ibbotson is a freelance violinist. The OAE give the British premiere of Anton Safronov’s completion of the Unfinished Symphony on Tuesday at the Royal Festival Hall, SE1 (0871 6632597)

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