The population is ageing. People live longer and are fitter. Yet one of Ming Campbell's problems as leader of the Liberal Democrats was that he was perceived to be too old at 66.
Admittedly, he did look older than his age. But Winston Churchill first became prime minister when he was 65, admittedly at a time of great national emergency and was 80 when he left office. 'Supermac' was 62 when he took office and his successor, Sir Alec Douglas-Home, had turned 60. That was the age at which Harold Wilson felt he ought to retire.
Of course, only a few people knew at the time that Churchill had had a stroke in his last term as prime minister. Today, there is much greater transparency about the health of politicians. Given the rapid pace of technological change, a politician can seem older than his chronological age.
I think the Liberals' problems are more fundamental than the question of who is leader, although their current ratings are among their worst for 20 years. Where do they position themselves on the political spectrum? They got some electoral dividends in 2005 for being perceived as to the left of Labour. But is that a sustainable position, given that many of their seats are vulnerable to a swing to the Conservatives?
Their great hope is a hung Parliament and a changed electoral system which they think would benefit them. But, depending on the system adopted, other parties such as the Greens and parties of the far right could benefit as well.