And to answer an earlier query, from an ATC point of view if we don't know (or you don't have ) a 3 letter code we will just write what you are calling yourself out in full-if you're on a flight plan the 3 letter will get printed on the strip, most NATS units have the callsign appearing next to the 3 letter code on the strip, where I work we don't so if its not one we know, I (or the assistant) has to look it up in a big ICAO book or (more normally) we ask the centre that is handing the flight to us. If no-one know it you will generall get called your 3 letter code phonetically. So to quote the earlier example, if we dont know that XBC01 is Newboy01, you will get called X-ray bravo charlie 01.
And just to clarify British Airways "Speedbird" is BAW not BA! But i'm sure you all knew that anyway
