YouTube hoaxer makes a very convincing Mozart

Norman Lebrecht, the seasoned and ever-alert musical commentator, thinks he and his readers may have uncovered someone making a very good stab at being Mozart. Three pieces have been discovered on the internet DIY-video channel being played by a pianist whose face can't be seen, all purporting to be new or obscure works by Mozart, Haydn and Mendelssohn.

In a time when lost items are turning up quite regularly now - Vivaldi, Mozart and Beethoven pieces have recently been found in far-flung files and libraries - Lebrecht decided to take the "Ask the Audience" option, by putting the Mozart piece on his blog, Slipped Disc, and asking readers. Swiftly the comments and judgments poured in, finding holes in the apparent catalogue numbers, in modulations, and (in the Haydn case) in "a dirty great doubled leading note, followed by parallel octaves. Definitely not allowed", admonishes Tom Morris.

Others have been rather admiring of the high quality of the hoax compositions, the Mozart and Mendelssohn both thought (despite the compositional flaws) nice to listen to. What may shock the general reader is the blasé reaction by one commenter, that pastiches like these are being written every day by music students across the world as an exercise in composition - an insight into the skilled education that music students take as read.

What's equally intriguing is how Lebrecht's readers have so very rapidly found something "wrong" about the pieces, instantly - as art historians and critics will say a picture is "wrong". The Haydn may have an error in classical syntax that's a giveaway, but the Mozart is felt to be "wrong" in part because the modulations (where one key changes into another) aren't interesting enough, which is entirely an artistic judgment about what people expect of that composer.

Fallible, partisan and unscientific such expertise may be, but until you can examine the DNA of a piece of music, it will remain by far the most instructive way to find out anything about art. And the day they do find the DNA of a piece of music will be the day the fun dies.

One section of listeners is now tracking down who the perpetrator could be - and they think they found a suspect in Chicago. Today someone has stepped forward claiming to be the hoaxer.

The question is: is this really the hoaxer, or another hoax? Surely he's going to have to produce another hoax as good as the others in order to prove who he says he is. Lebrecht thinks Beethoven's 33rd piano sonata is overdue.Terrific stuff.

• The story on Lebrecht's Slipped Disc