Peter pan theme music

The incidental theme tune that is playing throughout the film. Does anyone
recognise it? I am sure I have heard it in a film previously (possibly an
old film) and I am quite sure it is part of a classical piece. I have been
humming it to myself all the way home from the cinema and it is driving me
nuts now :-P.
Please put me out of my misery and tell me what it is called and what film
it is in.

Thanks
Nick