Well you
In 2006, European legislation will come into force that prevents discrimination on age. My understanding is that companies will not be able to enforce compulsory retirement on age alone - ie if as a pilot you are fit enough to pass a class 1 medical and competent enough to pass simulator checks etc, you cannot be forced to retire.
In BA (where pilots have a compulsory 55 retirement age) this may well see that restriction having to be removed, and flight crew being able to continue on beyond 55 to who knows what age. It is likely that a sizeable proportion of pilots would choose to extend beyond 55. For arguments sake if 50% go on to 60, then on average it will take 2.5 yrs longer for DEP's to get command. If the average pilots' length of service increases from 30 to 33 years, then is will take about 15-16 years to achieve a command, hence if you sign on as a 38 yr old ex RAF guy, you may not achieve a command until mid 50's.