Daniel Hannan is an MEP for South-East England, and a journalist, author and broadcaster. His most recent book is How we invented Freedom and why it matters.

Why now? What prompted David Cameron, apropos nothing in particular, to talk tough about Muslim extremism and deporting people who don’t speak English? There is, I think, only one explanation.

The proposal itself is utterly uncontroversial. I have never met a newcomer to this country who doesn’t want to speak English. Those who arrived too late to acquire fluency are, as you’d expect, determined that their children should have the advantages they lack.

Nor is official hectoring about language skills especially new. In Tuesday’s Telegraph, James Kirkup dug up a quotation from John Patten, then a junior Home Office minister, from as long ago as 1989:

“No one would expect or indeed want British Muslims, or any other group, to lay aside their faith, traditions or heritage. But they must not forget that for the child to prosper in Britain and to reach his or her full potential, he or she will also have to have fluent command of English.”

Well, obviously. You won’t find many British Muslims taking issue with the idea that their kids should speak the global language.

So why, 27 years later, again advance a proposition that no one is seriously going to oppose? And why garnish it with harsh-sounding talk about extremism and deportation?

Because this isn’t really about language lessons or about domestic extremism. It’s about the EU referendum.

We know that the Prime Minister plans to persuade us to accept the Brussels system by talking up the security angle. In his most recent speech on the subject, he tried to present EU membership as “not just a matter of jobs and trade but of the safety and security of our nation”.

This is not an obviously easy sell. Voters are alarmed by the deepening migration crisis. They fret that there might be another bout of trouble in the eurozone, with Britain yet again being forced to bail out a currency it didn’t join. Taking back control of our money, taxes and borders seems the safer option.

So the Prime Minister needs to make some Right-wing noises, ideally about Islamic extremism or immigration or both. It’s true that there is no obvious link between language skills and jihadism (the loathsome people who have left Britain to fight in Syria overwhelmingly speak English). And there is even less of a link to EU migration policy.

But a referendum is not a maths exercise. It is messy and emotional. A general sense of insecurity is putting some voters off the EU. The Prime Minister – I don’t blame him for this, he has a campaign to fight – aims to win them back by using the word security a great deal.

He can’t address people’s specific concerns about the European migration crisis, but he can create an inchoate sense that he is taking tough action. Referendums often come down to hunches and instincts, to the taste of the campaigns, to what we might pretentiously call their gestalt. Between now and June, David Cameron aims to come across as the hardest of hard men.

Never mind that nothing much is being announced. Never mind that it would surely make more sense to require people to learn English as a condition of settlement rather than trying to expel them later. Never mind, either, the concerns of many patriotic, Tory-inclined Muslims who feel that, even though the Prime Minister has a point, he needn’t have expressed it in a way that singled out one community. That singling out is, in a sense, the whole point: it’s what makes David Cameron come across as uncompromising.

The announcement is a sign of just how determined the Prime Minister is to keep us in the EU. As Tim Montgomerie wrote recently:

‘I underestimated Downing Street’s determination to organise everything in terms of avoiding Brexit. The go-slow on cuts, the living wage announcement, the retreat on tax credits, the extra money for defence: this pre-referendum behaviour is pretty boilerplate pre-election behaviour.’

Will it work? I’m not sure. One thing that being in politics has taught me is that voters are less impressionable than their leaders sometimes assume. The day after the Prime Minister’s announcement, some concrete news came from Brussels: unless Britain agreed to take quotas of refugees from other EU states, it would no longer be able to return illegal immigrants to safe countries.

I reckon most voters will see such Euro-blackmail for what it is. They will grasp that, if this is how Eurocrats treat us before we vote, we could expect far worse after voting to remain. It will be difficult, in such circumstances, to convince people that remaining in is the safer option.

For there is a truly vast irony here. While the Prime Minister could in theory try to deport migrants who don’t speak English, and while it is even conceivable that our politicised judges might uphold such deportation orders, he cannot apply the same test to migrants from the EU. They will continue to have the right to settle here as if they were UK nationals, English language or no English language.

In other words, the whole proposal serves only to show how little authority we have vis-à-vis the EU. The Brussels authorities, ultimately, can tell us whom to admit and in what numbers, and there is absolutely nothing we can do about it.