The unmissable fact is that of the nine MPs who have been assassinated, the first of whom was a Prime Minister, only two since have not been targeted by Irish Republican terrorists – presuming that David Amess can be added to that list, as is surely the case.

That’s over the course of 200 years.  Both have died well within the last decade.  Is that simply coincidence?  Or does it say something about our times?  I believe the latter – whatever the circumstances of David’s death may have been.

I never feared murder when serving as an MP, and neither recent death had happened when I stood down, back in 2010.  But I didn’t like the way things were going.

MPs were changing from being elected representatives, supported either by labour or capital, to professional politicians, funded by the taxpayer.  The transformation was speeded by the expenses scandal.

Much of the change was for the better.  The scandal was, after all, a scandal – one that arose because the expenses system was being used, in the absence of any real accountability and control, to supplement MPs’ salaries.

Furthermore, the old post-war world of capital v labour was breaking down: globalisation was internationalising the bosses and de-unionising the workers.

So it would have been impossible for the role of an MP not to adapt.  I’ve said it before and say it again: no generation of MPs have worked harder for their constituents than this one (including mine).

But if voters didn’t like the old world of the elected representative – the old trade union activist who had worked with his hands; the knight of the shire with his stack of paid interests – they don’t seem to care much for the one of the professional politician, either.

Part of the explanation is the collision of modern politicians with social media.  If you want to get a flavour of it, read Nadine Dorries’ piece on this site from three years ago.

“I want to see you, trapped in a burning car and watch as the heat from the flames melts the flesh from your face,” she wrote, giving us a taste of her experience of thuggery, abuse, threat and stalking.  It may have been extreme, but it was not unique.

Where words go actions follow – whatever may have happened today in Southend – and now David Amess lies dead, a man of whom I have never heard anyone say a bad word, and an unswervingly dedicated constituency MP.  Let me tell you what will happen next.

The outcry already taking place will morph into a consensus that something must be done (while the usual trolls rejoice at David’s death on Twitter).  And it makes sense for MPs to run more checks, for example, on their surgery appointments.

But any action will be marginal.  Ultimately, MPs can’t wrap a security fence around themselves, and must mix with the tens of thousands of people who they represent.  Few would wish otherwise and even fewer would attempt it.

So nothing much will be done, and the world will move on, our collective attention-span being what is is.  As it does, MPs and would-be MPs will make their calculations.  As will – and this is crucial – their families.

A trade-off will take place between the vocational pull of serving as an MP, plus the mass of other motives that lead people to want to stand for Parliament, and the possible consequences of doing so

Indeed, it is already happening: we noted three years ago the accelerating list of MPs retiring after only a brief spell in the Commons: the Jessica Lees, the Peter Heaton-Jones’, the Seema Kennedys.

Some of those who have gone were spurred by family illness, or didn’t like the Party’s direction of travel.  But others reached the conclusion that the game was no longer worth the candle.  Or their families did.

Tim Montgomerie wrote on this site in 2013 about reports that a sixth of Conservative MPs elected in 2010 “have divorced, formally separated or had long-term relationships break down since the election”.

I doubt that the equivalent proportion for the following three intakes has been or will be lower.  And make no mistake: the present reality of an unhappy spouse makes a much bigger impact on MPs than the prospect of physical danger.  At least as things stand.

For the moment, there is no shortage of people willing to stand for Parliament.  Whether there is a shortage of able people willing to do so is another matter.

My sense is that there is a slew of people on the Conservative side of the aisle, especially in business, who would have volunteered, say, 20 years ago, but won’t now: and certainly, the restrictions on their outside interests are a factor.

MPs are well-paid by any standard: they were in the top three present of earners when I last looked.  But many Tory MPs aren’t so by the standard of their peer group.  Which will always count in a world where people want to keep up with the Jones’.

In the raw trade-off between ambition and caution, ambition will doubtless continue to win out, and there will be no shortage of people willing to come forward to stand for Parliament.  At least for the moment.

But I begin to see circumstances in which that is no longer so: or at least in which no-one much is willing to put themselves forward other than freaks and fanatics.  Plus those who couldn’t find work elsewhere for the same pay.

If in each generation we get the MPs we deserve, that speaks less badly of this one than some claim.  It could scarcely be otherwise, given the change in constituency role.

But after Jo Cox’s murder, and Stephen Timms’ near miss, now David Amess is gone. Plus, in this ghastly roll-call, Andy Pennington – the assistant stabbed to death at the turn of the century as he tried to protect his employer, the Liberal Democrat MP Nigel Jones.

The only substantial conversation I had with David, at least that I can remember, was when he tried to persuade me to visit the Vatican.  He was Chairman of the All Party Parliamentary Group on the Holy See.

That post illustrated his Christian faith.  There was nothing self-dramatising, let alone morbid, about the cheerful presence that I used to see in the lobbies, but David would have known the old quote from the Gospel.

“Greater love hath no man than this, that a man lay down his life for his friends.”  And by the mere fact of coming forward to serve, David laid down his life for his constituents.

Like other forms of service, being an MP can cost “no less than everything”.  Our prayers and solidarity are with David’s family and friends.  His death is a loss to them that can never be made up. And a warning to the rest of us.