The BBC "rottweilers" Jeremy Paxman and John Humphrys think they have got Blair on the ropes because he failed to put a figure on the number of illegal migrants. They were particularly exercised that he didn't appear to know about an academic study commissioned by the Home Office, which is said to put the figure at 500,000. This "estimate" was featured heavily in the Sunday Times this weekend which mysteriously claimed that it had both been privately endorsed by the Home Office and suppressed. In fact Professor John Salt's report was published last autumn. He told me this week he felt the most charitable description for the Sunday Times piece was that it was a distortion.
"Neither I nor anyone else knows the size of the illegal population in the UK," he said. "Nor is there any effective methodology for producing one. No European country has produced an official estimate of its illegal population and no one has found a satisfactory method of calculation."
So where did the figure come from? The Home Office did ask Prof Salt to start looking at ways it might be possible to make an estimate. He looked at a number of other European countries where there had been amnesties and compared the number of illegal migrants with the recorded legal foreign population. Applied to the UK, he said this calculation gave a figure somewhere between 100,000 and 900,000 of which the mid-point cluster was around 450,000 to 550,000. He says there are no particular grounds for assuming that Britain is similar to the southern European countries involved. The only remaining mystery is why the fiercely anti-immigration Sunday Times chose to quote the 500,000 figure rather than 900,000. It must be the election campaign making them feel more responsible than usual.
