Over a hundred years ago, a man called Isaac got off a boat that docked at Hull – perhaps from Russia, maybe from Lithuania, or from one of the other Baltic States.  He may have thought that he had reached New York.  If so, he had many years in Britain to ponder his mistake, as he settled to peddle goods in Yorkshire, where he was unsurprisingly known, among those he did business with, as “Isaac the Jew”.  He eventually settled with his family in Manchester where, unlike most of his other Jewish neighbours, his daily newspaper of choice was not the Manchester Guardian (as the Guardian then was), but the Times.

Isaac was my great-grandfather, and his tale has left me with a sympathy for immigrants – and, perhaps, too, with an understanding of where much of the pressure on our immigration system comes from.  He was not just an economic migrant, because anti-semitism was on the rise in Russia and its empire.  But he was not exactly a refugee, either – at least, in the sense that the parents of Aylan Kurdi, the drowned Syrian boy whose fate in Turkey is shifting Government policy in Britain, were when they entered Turkey.  The Russia of his day was not engulfed in civil war.

In short, my great-grandfather was not unlike the mass of young men at Calais today who want to come to Britain: life in his home country was very unpleasant indeed, and he wanted a better life elsewhere – and who can blame him?  Like some of them them, he probably paid a gangmaster – or the nineteenth-century equivalent – to get aboard the boat that took him to Hull.  But unlike some of them, he didn’t try to break down a fence or smuggle himself into Britain. Whether or not this says something about him, it certainly says much about how the country he entered has changed since.

The scale of post-war immigration has been the greatest in our history, reaching a peak under Tony Blair and Gordon Brown, rising in New Labour’s early years by up to half.  This creates pressure on public services – schools, hospitals, roads, trains, houses: parents are less likely to get their children into local schools, waits for hospital operations are longer, houses become less affordable.  There is another side to the story: the NHS needs its foreign-born staff to work. None the less, not all of them speak English well – one of the signs of the integration problems that mass immigration brings with it.

My great-grandfather’s original life in Britain would have been lived in an island of Jewish life – his family and neighbours – amidst the great sea of the native English.  He would have been astonished by today’s multi-cultural Manchester, with its profusion of ethnicities and tongues.  The debate about the economic effects of today’s immigration rolls on, but the fullest Parliamentary inquiry to date found no evidence of “significant economic benefits”.  Most voters from all backgrounds want less immigration, but at present are getting more – indeed, much more: last month, it reached record levels.

They may well be willing to take more refugees from Syria, but not without taking fewer non-refugees from elsewhere – and at present, there’s no prospect of this happening.  Many will also ask: why Syria?  One answer is that Syria’s conflict threatens our own stability – but that is a political argument, not a humanitarian one.  If feeling for our fellow men and women is to be our guiding star, we should also take more refugees who are, say fleeing the Boko Haram insurgency, the ethnic conflict in South Sudan or the Yemeni civil war.

However, no dead child slaughtered amidst these horrors has left a name for the people of Britain to remember – because the plight of none has been first caught on film and then projected by media, to the point where the mighty apparatus of government flinches before it.  Today, David Cameron, U-turning on his position of two days ago, will announce that Britain will take more refugees from Syria.  He reportedly believes that opening borders, agreeing quotas and taking more will only encourage traffickers and “increase pull factors” – which can only mean that he thinks his new policy is wrong.

Most of my time is spent in London, and I can see that the capital is for this change of policy – or, rather, what the capital has come to stand for.  The Twitter flashmob wants more refugees.  The BBC wants more refugees, and has not so much abandoned impartiality on the matter as shown no sign of understanding it.  Most of the broadsheet commentariat wants more refugees.  Some politicians want more refugees – but, then again, Yvette Cooper has a leadership election to win (having usually voted for stricter controls) and Boris Johnson has a leader to outflank.

Of the Tory MPs who called early for more refugees one, David Burrowes, sits for an ethnically-mixed seat in Enfield and another, Nicola Blackwood, for a constituency which, since it contains a university, is unlike much of the rest of the country.  To the best of my knowledge, not one of those who raised their voices before the Prime Minister’s change of heart represents a constituency outside the prosperous south-east, with one exception – Johnny Mercer, who proves what many of us already know: namely, that soldiers are usually more and not less humane than the rest of the population.

Blackwood and Burrowes are committed Christians, which informs the view they are taking: none the less, the overlap between location and view is striking.  What does the rest of the country think? Your guess is as good as mine, but it might be that asylum applications should be processed off-shore; that aid should shift further to the camps in the middle east and elsewhere (refugees are living in them rather than waiting at Calais); that we help to build the Singapores and Hong Kongs of today in North Africa, as Peter Franklin has suggested, and that the antique conventions on asylum are modernised.

They might also think that if we left the EU we could trade off fewer economic migrants from the European mainland for more refugees from Syria and elsewhere.  I would be happy with such a deal and others would not be – but, either way, it is not on offer.  What will happen is that we will have the refugees but not the control, without any evidence that the British people want it. This is Snapchat politics – demanded today and forgotten tomorrow, when the crowd has moved on to the next thing to engage its seconds-long attention span.

The Prime Minister has taken a holding position, sniffed the wind – and changed it.  He will have been advised that this is the only way “to change the narrative” and “to move the story on”.  He will probably announce that Britain will take many more than the 216 it has already taken and many fewer than the 10,000 that are being presently demanded.  At this point, the cry will go up for more to come and from more places: David Blunkett is already calling for 25,000.  Cameron may or may not budge further, but the signal has already been sent: press this Government, and it will fold.