There are three reasons for leaving a political party and joining another one.  First, because you have left your Party – in psychological terms, anyway. In other words, you come to realise that your own view of politics has changed, and that you should therefore change your party too.  Second, because your Party has left you: although your approach to politics is still the same, uthas moved to the Left or the Right or in some direction you don’t like.  The third is for personal advantage.

Paul Johnson, Kingsley Amis, Hugh Thomas and the group of former socialists who left Labour to join the Conservatives in the late 1970s followed the first.  Their shift was a sign of the Thatcherite age that was to come; Reg Prentice’s defection in Parliament was another.  I will draw a tactful veil over the third.  Is Jeremy Browne an example of the second?  In this morning’s Times (£), he suggests that if the Liberal Democrats didn’t exist, it wouldn’t be necessary to invent them.

“I’m not sure it would be necessary to invent an ill-defined moderating centrist party,” he says.  His Times interview today follows a book, Race Plan, which calls for a cut in the top rate of tax to 40p, school vouchers, insurance payments for health, the scrapping of the Climate Change department (up yours, Ed Davey!) and a new hub airport in Kent with up to six runways. He is also rather sharp about Nick Clegg, who he claims has lost his way. “Maybe I’m a more defiantly loyal ­supporter of Nick Clegg than Nick Clegg is of himself,” he says ingeniously, though not necessarily ingenuously.

As Mark Wallace has written on this site, there are Conservative MPs who share Browne’s liberal views on immigration, and his support for Britain’s EU membership.  (There are not that many who would come out for his policy prescriptions, at least not all at once.  In this sense, the Taunton Deane MP is “to the right”, as the debatable designation goes, of much of the Tory Parliamentary Party.)  In British politics, where liberalism ends and conservatism begins isn’t just a matter of academic debate.  The modern Tory party is a descendant of both the Conservative and Liberal nineteenth-century parties.

Defections can be a sign of a shift in the political wind.  The defections to the Conservatives under Thatcher are one example.  So are those to Labour under Blair: Alan Howarth, Shaun Woodward, Quentin Davies, Robert Jackson, Peter Temple-Morris.  Were Browne to turn blue, it would be a reminder that there’s little point in having two left-of-centre parties in Britain, with its electoral system that favours one big party each of the Left and the Right – a view he’s evidently reached himself.

Browne used to be clean-shaven.  Then he grew a beard.  The Times reports that he has now shaved if off.  The rapid sporting and removing of beards is an infallible sign of a personal crisis of political identity.  Come on in, Jeremy!  The water isn’t always lovely.  But you’d be happier splashing about with George Osborne (Browne praises the Chancellor for his liberalism in today’s interview) than shackled to Nick Clegg.