Not so long ago, MPs were elected representatives, funded privately.  The Conservatives represented capital; Labour, labour.  The politics of this post-war system were class-based, and there was a strong local element to candidate selection.

This settlement began to change rapidly from about the time of the Nolan Report.  MPs became less like the interests they represented and more like each other.  The grip of the two main parties on Parliament weakened but strengthened on candidates.  There was a shift from private to public funding.  MPs became professional politicians paid for by the taxpayer.

Whatever else may be said of these developments, they don’t seem to have boosted mutual satisfaction.  Turnover rates have climbed.  In Cameron’s Children, this site noted that “almost half of the 30 candidates we originally surveyed had not fought a constituency before”.

That was in 2015.  Aidan Burley, Lorraine Fullbrook, Jessica Lee, Chris Kelly, Louise Mensch, Laura Sandys and Mike Weatherly had already left after serving one term only (or less).  By the time we published May’s Men and Women, two years later, the list of new MPs included Mims Davies, Bill Grant, Peter Heaton-Jones and Seema Kennedy.

All are stepping down for this election, as are several other MPs elected as recently as 2010.  These include Jeremy Lefroy, Sarah Newton, Jo Johnson, Claire Perry and Nicky Morgan.  Bill Grant is leaving after serving one term only.

It should come as no surprise that such Parliamentary veterans as David Lidington, Patrick McLoughlin and (especially) Ken Clarke are quitting the Commons – in the latter’s case after entering it as long ago as 1970.  But women especially seem to be quitting after relatively short Parliamentary careers.  What is going on?

Part of the answer reflects badly on MPs themselves.  If you send much of your power outwards, to the EU; sideways, to the courts; and downwards, to the devolved institutions, then don’t be surprised if voters become resistant to backing you and funding you – especially in the wake of the Iraq War, “expenses” and the financial crash.

Another part shines a harsh light on their constituents.  Modern MPs must expect consumer resistance.  But much of what happens on social media and off it is tantamount to workplace abuse.  A woman MP has been murdered.  Others are unwilling to put up with it.

It is important not to exaggerate the scale of change.  Most new Conservative MPs, according to this site’s studies, are like their predecessors: privately employed, married, previously active in the Party.  Fewer are white; more (openly) gay; more, noticeably, were educated at state schools.  But there is continuity.

It is also necessary to see context.  Tory MPs tend to divide into two classes, like H.G.Wells’ Elio and Morlocks.  The former sit for so-called “safe” seats; the latter for marginal ones.  A McLoughlin or a Lidington will get by without too much local difficulty, just as their predecessors did.

Meanwhile, the shift from the elected representative to the professional politician model has been good news for constituents.  The days when the local MP could ignore the latter, or visit his seat only occasionally, vanished a long time ago.  That’s the effect of consumer competition for you over the years, with the emergence of the SNP, UKIP, the Greens and the Liberal Democrats.

We are moving from a model in which many MPs sat from late youth until early old age to one in which more serve for one or two terms – as the Editor of this site did.  That has pluses and minuses.

One plus is that although the number of applications for the Conservative list seem to have fallen in recent years, there is no shortage of aspirants willing to stand.

A minus is that a bigger churn means less experience.  The Commons needs former Ministers who, on hearing a new idea, can say: “we tried that and it won’t work”.  Or, better: “we tried that and it didn’t work.  But here’s how it might work – based on my time in office”.

That avoids endlessly reinventing the wheel.  A Commons in which nearly everyone was, say, a second term MP, aged perhaps 45 or so, would be packed with energetic constituency campaigners but fewer older statesmen and women.  And it needs some of the latter.

Clearly, there is something wrong with a system in which former Prime Ministers avoid the Upper House because they don’t want to declare their earnings. And a culture in which women MPs especially are bullied on social media in the way that some are.  And a Commons in which someone like Morgan, who has specialised recently in trying to keep the Conservative family together, feels she must stand down.  And a Party which doesn’t give local Associations more of a say in the selection of their successors.

Perhaps what is needed most of all is a sense of perspective.  Most MPs don’t enter Parliament to make hay – and if they do, they’re looking in the wrong place.  Rightly or wrongly, they stand for election because they want to promote a cluster of instincts, policies and reflexes.  Some are not very good at it.  Most work away at trying to do it properly.  For every Keith Vaz, there are perhaps five McLoughlins or Nick Hurds or Lidingtons, at least.

We will be told that there is an “exodus of moderates”.  That is correct only if one identifies moderation with political support for EU membership. Most of those retiring are MPs who have been in the Commons for several Parliaments.  Certainly, these tend to be more pro-EU than recent arrivals.

But until a full study of their successors has been made, it would be premature to complain of a shift to the right – or anywhere else.  Especially with a Conservative Government committed to high public spending all around, such as on the NHS and on infrastructure.

If that isn’t a conclusion that works for you, it may be worth going back to the start.  Should MPs be elected representatives, funded privately?  Or professional politicians, supported by the taxpayer?  If we can’t decide, no wonder the established parties have been shaken and turnover rates have risen.

Perhaps Brexit will provide MPs with the scope and space to rebuild.  So it is today in “the High Court of Parliament” where, as our greatest modern poet put it, ” ‘thy’ high lamp presides with sovereign / equity, over against us, across this / densely-reflective, long-drawn, procession of waters”.