I have never had much time for Andrew Green - the absurd extrapolations of questionable statistics that his "Migration Watch" group publish periodically serve only to get a few scare story headlines rather than actually contributing to the debate on migration.
Since Mayor Boris Johnson- a figure who increasingly impresses me- mused publicly about the idea of an amnesty for illegal immigrants, it was only a matter of time before Green would publish some swivel-eyed nonsense.
The scare story headline was that "legalising" illegals would cost £4 billion. However even before we start, we find that half of this is somehow attributable to the partners and families of illegals- many of whom are actually already legal British tax payers. So even on Mw's numbers, then the cost falls by half to the still eye-popping £2 billion.
Then you look at the assumptions.
Essentially Migration Watch assume that those who are working would not only not pay tax, but would instead become claimants on the state.
As a former civil servant, Sir Andrew knows more than most about being a cost to the British tax payer. However the vast majority of immigrants to the United Kingdom- illegal and legal alike- would regard it as either pointless or a matter of some shame to claim on the State.
As usual, Migration Watch's numbers are simply meaningless scare tactics to promote a xenophobic and unpleasant agenda.
At a time when the population of the UK is actually falling sharply- with Poles returning home, and the foreign high-rollers in the City of London following them out of the door, we will increasingly struggle to compete as further skill shortages emerge.
In such circumstances, the anti-migration lobby may get what they wish for... and then really wish they hadn't.