The most troubled part of David Cameron's EU renegotiation is his bid to impose a four-year ban on migrants claiming in-work benefits and social housing. Cameron maintains that the demand has not been rescinded, despite members states' opposition, but at the end of last week's summit EU president Donald Tusk stated: "To me the clearest message is that no one including David Cameron is ready to accept discrimination."

To have any hope of agreement, Cameron would have to extend the four-year ban to some or all British citizens (thus avoiding penalising migrants), an option that Iain Duncan Smith and Theresa May are resisting. Many Conservative MPs regard the initial proposal as far too modest, arguing that it will do little to deter migrants.

But the Polish-born Daniel Kawczynski has sounded an alternative note. In a statement to fellow Tory MPs, seen by the NS, he wrote: "Speaking as the only British MP born in Eastern Europe, the coverage on benefits is a distraction as the majority of Eastern Europeans here have to come to work. Their contributions in income tax outstrip any benefits they may get many times over. If we are to be convinced of staying in, we need to get back to bread and butter constitutional reform."

HMRC recently refused a request by Jonathan Portes to publish the number of "active" National Insurance numbers issued to migrants (to determine how many were paying tax or claiming benefits), warning that it would be "unhelpful to the negotiation process". Last month, No.10 briefed that 43 per cent of EU migrants who arrived in the last four years were claiming benefits (a figure later shown to be between 37 and 45 per cent) but did not release the data behind the figures. Independent research has found that migrants are marginally more likely to claim in-work benefits than British nationals (though many will also be paying tax) and that they are less likely to claim out-of-work benefits.

But as Kawczynski suggests, by elevating the issue of welfare above all else, Cameron has encouraged the misperception that migrants claim far more than others. One German official recently asked of his approach: "Why has Europe’s third-biggest economy and biggest military power reduced a debate on its EU future into a question about social benefits?"

Tory MPs, meanwhile, are warning that even if agreement were reached on a four-year ban, other incentives for migrants to come would remain. As I predicted in July, the new National Living Wage, which will give the UK one of the highest minimum rates in the world (starting at £7.20 next April and rising to £9 by 2020), is being cited as a new draw. Economists point to the UK's record level of job creation as the primary attraction for migrants.

For these reasons, Cameron may well take Kawczynski's advice to refocus attention on the three other aspects of his renegotiation: an opt-out for the UK from "ever closer union", greater protection for non-euro member states and a commitment to increased "competitiveness".