Sir Robert Vansittart, chief diplomatic adviser to the British Foreign
Office in 1939, was brought in by his friend
Miklós Rózsa to write the
lyrics for one of the songs in
The Thief of Bagdad (1940).
Sir Robert had had much experience serving in the Middle East. He spoke
various languages of the area and was well versed in the old stories
and mythology. So when Korda wanted to put together a film that was an
amalgam of various stories from the Middle East, Sir Robert was willing
and able to help them.
However, he was still serving in the diplomatic corps and didn't want
to use his own name in the on-screen credits for such a light-hearted
film (he had previously contributed to
Queen of Destiny (1938), but that was a worthy
film about Queen Victoria). So it was agreed that he would take the
name of the studio (Denham) as his on-screen surname.
The lyrics he wrote for "I want to be a sailor" are very catchy and
memorable. Especially with that knowingly awful rhyme "I want to be a
bandit, can't you understand it".