Many of the responses have tended to be around the cushey long-haul captain (on his umpteenth marriage) in a 'milk and honey' airline and why should he want to continue working and holding some 'poor' first officer back from promotion because surely he must be 'beyond it' from now. There has also been a lot of finger-pointing at the employers for not keeping pilots on after certain ages.
Well let's consider the real world out there. There are hundreds and hundreds of pilots that have had airlines go bust around them causing chaos to future retirement financial planning. There are also hundreds of pilots who have had their pension provision plummet, either due to unscrupulous airline owners or to the vagaries of the values of money-purchase pensions. There are also hundreds of pilots who have had no company pension provided by their employers. Those pilots would all like to have the option to continue working to be able to build up to what they probably had expected to be able to retire on but is now just that bit (or quite a bit!) further away.
Ability to continue should be seen in context: one of the marvels of the modern western world is that on average people are living a lot longer and are remaining fit and capable for a lot longer. In the most tightly regulated industry in this aspect, medical fitness and operating competence should not have any arbitrary age consideration but should be considered on an individual basis. A 70-year-old has been into space, so flying an airliner should not be limited by age, as long as there is the correct regulatory monitoring.
The big problem here is that UK law prohibits anyone from acting as a captain or a co-pilot on any public transport aircraft over the age of 65 (this is not a 'hire and reward' issue as there is not the same age limit for various other 'hire and reward' jobs like flying instruction and other aerial work). UK law is also raising the age that one is able to draw a state pension above 65. This means that any pilot who has suffered a financial catastrophe and has poor pension provision is not allowed to continue to work in his job over 65, but is also not allowed to have the top up of the state pension that he has paid towards for all his working life. This issue shows that any claim by any politicians in Britain that age discrimination is illegal in Britain is a blatant lie.
And final to those first officers who have been grumbling about captains not retiring and thereby not 'releasing' command positions for them: just sod off, stop being so self-centred and greedy, and wait your turn!!