On Wednesday David Davis used the shocking news that only 90 per cent of people living in Britain were born here to flog the immigration plan that he unveiled last week.

“This is yet more evidence showing the real need for a limit on non-EU migrants coming to the UK,” he told The Daily Telegraph. “Only by doing this can we control immigration.” Presumably he believes his bath won’t overflow if he turns the hot tap off but leaves the cold tap running.

If Mr Davis thinks that the UK’s migration “problem” is coming from non-EU countries he should spend a morning at Heathrow or Stansted and look at the length of the respective immigration queues. The vast majority of migrants to this country come from the EU: there are no limits to their numbers, they don’t need to have a job before they arrive, there are no skills or language tests, they are entitled to receive welfare shortly after they arrive, and once they are here they are almost impossible to deport.

Every country has a right to control its borders and that is how Britain has decided to control its. People from the Commonwealth are entitled to feel that there is something not quite right about this. When the doors to this country were closed to them they were told it was nothing to do with their colour, oh goodness no, it was about large numbers of migrants from very different backgrounds. To prove it wasn’t about colour, the doors were closed to Canadians, Australians and New Zealanders too.

Citizens of the Commonwealth mightn’t have liked it but at least it was non-discriminatory: the door was closed to foreign and Commonwealth alike. Can somebody please explain the fairness and sense of the current regime, which allows an illiterate Romanian peasant, whose grandfather fought for Hitler, unfettered access to the place, but which effectively bars a Canadian or Indian BA whose grandfather fought for the Crown?

Mr Davis is right, of course, when he argues that controlled migration is desirable. The problem is that you can’t have migration numbers that are a bit controlled any more than you can be a bit pregnant: either the numbers are capped or they aren’t.

Leaving aside illegal immigrants, asylum-seekers and resettled refugees of which it takes almost none, Britain has two sources of migrants: those from the EU (no restrictions) and those from outside the EU (carefully selected).

So why is Mr Davis proposing that Britain reduce the one part of its immigration programme over which it still has control? At present being a non-EU migrant to this country is like queueing outside a night club with a particularly capricious doorman. He’s telling you the club is full tonight or you’re not dressed correctly, but he keeps raising the rope to an endless stream of no-better-dressed “regulars”.

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