On our company BALPA forum there is much discussion about how BA is going to find all the pilots it's going to require over the next few years. There are a variety of factors effecting this, one of them being a bulge of people coming up to retirement in the next few years. This is a bit of an unknown because EU age regs may mean that a compulsory retirement age of 65 is illegal. But the fact is many of these guys will retire by choice, especially as they begin to get their final salary pensions back up to what they had planned to have at 55. When these guys eventually start to go in significant numbers I (and many much more knowledgeable than me) reckon the requirements will drop a long way.
I have to say that all this is based on educated guessing and nothing more.