Anthony Hilton: So much for George Osborne’s promise of tax riches from Swiss accounts crackdown

When Chancellors of the Exchequer find it hard to make the sums add up on Budget Day – which happens most years – they usually promise to balance the books with a crackdown on “those who don’t pay their fair share” and “ those who exploit loopholes and use tax havens”. Thus the missing billions are produced almost by magic, an embarrassing hole in the national accounts is plugged, and the Chancellor’s reputation for financial literacy survives another Commons mauling.

The game started with Gordon Brown and has been continued by George Osborne, and to our shame the press has let both of them get away with it. We have taken at face value their word that these sums actually exist. We never check afterwards to see how much money has actually materialised.

We should. On Tuesday I had breakfast with a top team from the Swiss Bankers Association, who talked about what had happened since the signing of an agreement with Britain last year in which the Swiss agreed to assist in combating tax evasion by providing much more information about Britons with Swiss accounts.

This was the deal the Chancellor had said a few months earlier would bring in between £4bn and £7bn of hitherto unpaid taxes.

Much to the disappointment of Her Majesty’s Revenue & Customs, it has not quite worked out like that. In fact, according to the Swiss, the total collected has been only about £1.25bn, but even this is an exaggeration. Because of various technical issues quite a lot of it will flow back and the eventual outcome could possibly be as low as £700m. Such a figure would be a mere 10 per cent of the maximum sum that Mr Osborne had confidently told us could be out there.