The new treaty follows the OECD Fiscal Committee's recommendation in April that its members ban anonymous accounts and require identification of customers. Under the treaty, countries must also require banks to keep accurate records of accounts and report suspicious transactions. In addition, accounts must be open to inspection by domestic law enforcement officials. Money laundering is criminalised, with sanctions against the people who do the laundering, counsel it, or acquire the ill-gotten gains.

However, the treaty does not go as far as the OECD's recommendation that countries re-examine existing practices - presumably with a view towards changing them - that prevent tax authorities having access to bank information for purposes of exchanging it in criminal tax prosecutions. In addition, the treaty doesn't deal with correspondent accounts, These accounts pool funds from numerous bank branches and customers, which means they remain anonymous and can come in quite handy to move funds around discreetly. Millions of dollars stolen by Raul Salinas, the jailed brother of Mexico's ex-president, moved from Mexico to Switzerland through a Citibank correspondent account in New York. "Shell" companies will also still get away with concealing the names of true owners and instead list nominees, whose names are often supplied by banks and company registration firms.

Mr Blum is aware that the UN's latest treaty does not go the full stretch, but he is undoubedly on the same crusade as US Treasury chiefs Larry Summers and Stuart Eizenstat, who would single-handedly wipe out money laundering and tax evasion in one fell swoop if they could. Blum said: 'Are there other things that have to come? You bet, but we're starting down the road. There are too many countries still very nervous about opening the books. There are countries that still make their livings assisting people evading taxes somewhere else. That's a very sticky issue.'

In the meantime, countries that decline to sign the treaty could get a dose of what the US did to a number of offshore centres this year: advise their banks and financial institutions to treat any transactions with suspicion and extra due diligence, and as every offshore financial centre knows, that's not good publicity.