By Claire Doole in Geneva

Eleven of the world's biggest banks have launched a global alliance against money-laundering.

The UK's Barclays Bank, Switzerland's UBS and Citicorp of the US are among the banks determined to clamp down on the organised crime syndicates who deposit an estimated $590bn of dirty money in banks worldwide every year.

They have signed a new code of conduct, a copy of which has been obtained by the BBC ahead of the official announcement in Zurich later on Monday.

The code is aimed at preventing organised crime and corrupt political dictators from stashing their dirty money in some of Europe and North America's biggest banks.

It puts the burden of responsibility for checking the authenticity of the client and his money squarely on the shoulders of the banker.

Toughest measures

Before opening an account, the banker must carry out thorough checks, particularly if the client comes from a country where corruption is rife.

For the first time, trustees depositing money will have to reveal the identity of their clients to the banks, as well as to any criminal investigators.

Up to now criminals, protected by a trustees' code of confidentiality, have often escaped detection.

The banks are duty-bound to report any suspicious activities to the authorities, as well as to set up special anti-money laundering departments.

The measures do not carry any criminal penalties for non-enforcement, but experts say they are the toughest yet adopted.

Sanctions threat

They come after a series of high profile cases in which banks accepted dirty mony from the late Nigerian dictator, Sani Abacha, and from those close to the former Yugoslav president, Slobodan Milosevic.

The establishment of the code follows threats of tough action from the members of the G7 richest nations against countries which permit money laundering on their territory.

The banks involved are UBS, Barclays, Citigroup, Deutsche Bank, HSBC, JP Morgan, Chase Manhattan, Societe Generale, Bankers Trust, Banco Santander and Credit Suisse.