"In Britain new migrants from the EU contribute more to the exchequer than they take out." - The Economist, today.

This point is often made, especially by economic liberals. But what if we take a wider view?

That net financial balance relates to now (and by the way, it's not clear whether it factors-in HEW costs for dependents). But has anyone forecast the lifetime tax contribution of the incomer and weighed it against his lifetime claims on State expenditure? I'm asking because I don't know.

Coming back to the present, if an incomer takes work that could otherwise have been done by someone already in this country, should we include on the debit side some of the costs of keeping the latter unemployed? That calculation is not simple: there are ramifications in terms of physical and mental ill health, family breakup increasing the need for social housing and welfare payments, children requiring special educational provision, more spending on policing and the justice system, etcetera.

Also, if European-wide movement of labour is uncontrolled, the law of supply and demand means a downward pressure on wage rates. That implies less tax raised from workers overall, and following on from that (in a socially supportive economy) more financial assistance in the form of in-work benefits.

Is it that no-one has done the sums, or have they done so and are keeping quiet because it spoils the narrative for big business?

A different argument in favour of immigration is the one about demographics. I'm not saying the answers are easy. My general point is that we need a proper holistic examination of the issues.