This is a confusing time to be a talented young musician called Daniel Cohen. The problem is in the name - there are two musically-gifted Daniel Cohens currently making their mark, and that is not the only case of mistaken identity the young composer is having to deal with.

"Everyone thinks you're my son," cries Gail Cohen, director of marketing at the British Film Institute when Daniel arrives to be interviewed about the score the BFI has just commissioned from him.

Gail, visibly kvelling, seems as proud of his achievement - this is his first commissioned score - as the 23-year-old Cohen is himself. The recent graduate of London's Royal Academy of Music has been asked to set music to the very first film directed by Alfred Hitchcock, whose early silent works are being restored and scored by the BFI as part of next year's Cultural Olympiad.

But while his new patrons have made much of Cohen being the same age as Hitchcock when he directed The Pleasure Garden, they have merely added to the confusion. Hitchcock was 26, the same age as the other Daniel Cohen, a conductor who is a protege of Daniel Barenboim.

More Hitchcockian yet, both Cohens were until recently studying side by side at the Royal Academy. However, the BFI's Cohen explains that he was on a quite different path from Barenboim's Cohen. "He is primarily a conductor, while I was studying composition," he explains.

The director is such an inspiration to my work

It was Cohen's teacher at the Royal Academy who was responsible for putting his name before the BFI when he heard of their Hitchcock project. "He knew my music very well, and that Hitchcock was such an inspiration to my work," Cohen says. "It was the movie The Lady Vanishes that made me realise what I really wanted to do was write music for film."

Bernard Herrmann, the composer most closely associated with Hitchcock, has been as much an inspiration as the director himself, admits Cohen, who plays piano and bassoon. He especially admires the rejected music for Torn Curtain over which the director fell out terminally with his Jewish score-writer.

"Herrmann wrote it for 12 horns. It was never used by Hitchcock. But you can listen to it on YouTube," Cohen says.

Another inspiration was the music department at Cohen's south London comprehensive. "It was brilliant," he says. "That's how I came to go all the way to grade eight on the recorder. I started at age nine in a group, and the teacher was so great, I never wanted to stop."

He took up the bassoon, another of his instruments - he also plays the piano - because he realised it would be a strategic aid to composing. "I learned it so I could play with orchestras. Bassoon players sit where they look over all the other instruments, except the percussion behind. That teaches you so much."

His works to date include a concept album inspired by the music of Pink Floyd and Led Zeppelin that his father introduced him to, which he hopes will be released before the Hitchcock film premieres next June.

The intention is to record the Hitchcock music after a few live performances - "somewhere a little more interesting than a conventional cinema". While he cannot set down actual notes until the restoration of every frame of The Pleasure Garden is complete, Cohen already knows he will hark back to the work of Hungarian composer Miklos Rozsa for his structural inspiration. "He wrote the score for Double Indemnity, and came up with the idea of dividing it into themes around the action, rather than leitmotifs linked to individual characters.

"As for the instruments, I'm thinking clarinets and saxophones."

He feels The Pleasure Garden deserves a lot more respect than it has so far attracted. "It was a blueprint for all Hitchcock's later work. All the themes are there - the voyeurism, the experimental camera work, the cool blondes."

What he hopes such a spectacular showcase so early in his career will do for him is introduce him to distinguished film-makers who might never otherwise notice him. "Getting visibility is vital for a young composer, and I hope showing I can tackle a large project like a film score before I'm 25 will mean I shouldn't have too many regrets about missed opportunities in the future."