“The worship of youth has diminished – perhaps generally – in recent years.” So said Vince Cable a couple of weeks ago in a newspaper interview which inflamed speculation he’d be partial to a tilt at leading the Lib Dems. It also prompted various politicians-are-getting-younger pieces in the media.

LibDemVoice’s Mark Pack took the time and trouble to dig out the data. He showed that while the trend-line in the first half of the last century was for prime ministers to get older, in the 50 years since there has been a movement towards younger premiers (James Callaghan being the main outlying exception).

Meanwhile Philip Cowley, professor of parliamentary government at Nottingham University who runs the Revolts website, has looked more broadly at politicians’ ages. And the reality is there’s not been much change over the last half-century in the ages of MPs:

In 1964, the median age of Conservative MPs was 45. In 2010, it was 47. The median age of Labour MPs in 1964 was 52; in 2010 it was 52.

Nor are party leaders getting particularly much younger:

The current tranche of leaders are younger than the post-war average but not so exceptionally younger. Ed Miliband, for example, was 41 when he became Labour leader, but so too were both Neil Kinnock and Tony Blair. Nick Clegg was 40 when he became leader of the Liberal Democrats, but so was Charles Kennedy, and David Steel and Jeremy Thorpe were both just 38 when they first led the Liberal Party.

However, they are getting less experienced — at least in terms of time spent in parliament, though not necessarily time involved in politics:

Of the 53 candidates for the leadership of the three main political parties in the 16 contests between 1963 and 1994 only five had less than a decade’s experience in the Commons at the point at which they stood. Collectively they constituted fewer than 10 per cent of all the candidates. By the current tranche of contests, by contrast, a majority of the candidates had had under a decade’s experience in the Commons, including 83 per cent of those who came first or second in their contests. … It is not the case that the leaders are inexperienced because they are young, more that they are younger because they are so inexperienced. The explanation lies in the changing nature of ‘experience’. All three of the current leaders had significant political experience before they entered the Commons.

David Cameron was a special adviser in the Major years, Ed Miliband in the Blair years, and Nick Clegg worked in Europe’s corridors of power for over a decade. In other words, all had extensive parliamentary experience, albeit more on the fringes than the backbenches.

Professor Cowley’s conclusion?

Despite the recent scare about the growth of the ‘career politician’, they remain a minority in the Commons as a whole, with plenty of MPs who have a broader experience of the world. But for those who want an accelerated route to the top, the career politicians now looks like the only game in town.

Which is a bit depressing.

* Stephen was Editor (and Co-Editor) of Liberal Democrat Voice from 2007 to 2015, and writes at The Collected Stephen Tall.