How many pilots???????????

[Tom Bell-Weed]

I'm new to the civil side of PPRuNe being a military type, but hope someone on this side can give me a pointer to some information I'm looking for. I'm doing a paper on why and when pilots leave the RAF and as part of that I'm looking for information on the total number of pilots engaged in the British Civil Aviation sector at any one time. Does anyone know of a site, or an organisation, which monitors the numbers involved, or even trends? Even if it's just total numbers on an annual basis it would still be useful.
Grateful for any tips received.

Tom