Mr Cameron does nothing on immigration, because he can't

Prime Minister David Cameron said migrants will not get benefits for four years. Credit: PA

One might argue that David Cameron has just given a speech about a problem that doesn't exist.

As you would expect, here at ITV News we try simply to concentrate on evidence based analysis. This is what we know our audience wants and what we are legally mandated to do.

So every time there is a story in the papers about benefit migrants or NHS tourism, we dutifully go off to investigate and try to establish the facts. And every time, the answer comes back the same; it isn't really a problem in the way that some are suggesting.

The basic facts seem to be that migrants come here to work, drawn by the dynamic nature of our economy. They are not particularly lured by benefits and certainly not by the NHS.

Both the OBR (the government's maths and spending watchdog) and the independent Institute of Fiscal Studies repeatedly argue that immigration is good for the public finances, because many European immigrants come here, work and pay tax - and then, often, go home.

So we haven't had to pay to educate them and we don't have to pay to care for them in old age. Or to put it another way, we get their economically productive years - and someone else has to pick up the bill for the rest.

Some argue that paying child benefit for children left behind in Poland is a particularly good idea because that way we don't pay to educate their children either, as we would if they were here.

The issue, if you think there is one (and clearly a lot do), is the sheer number of people coming here.

It doesn't seem to be increasing unemployment, but one might reasonably argue it is depressing wage inflation.

Today, Mr Cameron did nothing whatsoever about this for the simple reason that he can't.

Our European partners - pretty much all of them - simply won't let us.

Even if we left the EU, it is not clear it would make much difference unless we wanted to go back to square one and leave the Economic Area and the single market as it stands and try to negotiate our way back in from outside.

For an economy as big as the UK's, this would be an enormous and very risky step that few politicians outside of UKIP seem really willing to contemplate.

So he has changed quite a lot around benefits. But on the core issue of immigration itself and freedom of movement, the message of this speech is; no change.