Another �7m of suspected terrorist assets has been frozen in the UK over the last week, the government has said.

It brings the total of assets belonging to suspected terror organisations frozen in the UK to more than �70m.

Chancellor Gordon Brown told the Commons on Thursday he had ordered the blocking of assets belonging to 46 organisations and 16 individuals, and that offshore financial centres were being specifically targeted.

A new list of groups thought to have links to terrorist suspect Osama Bin Laden, issued by the US, was circulated overnight to UK financial institutions.

The list of organisations and individuals are suspected of having committed terrorist acts, or being at risk of doing so, or of supporting terrorism.

It includes the al-Barakaat multi-national, which has offices in Europe and the United States, but which has vehemently denied any terrorist links.

A second network is al-Taqua, a band of companies in Switzerland, Liechtenstein, the Bahamas and Italy controlled by Youssef Nada, a naturalised Italian citizen.

Doubts it will work

Some of the �70m total was frozen following UN Security Council resolutions dating from before 11 September.

The UK Government had already issued three lists of organisations and individuals whose assets it wants to freeze.

The groups are as varied as the republican dissidents the Real IRA, Basque separatist organisation ETA, Peru's Shining Path and the Japanese cult Aum Shinrikyo.

However, many analysts express doubt over the feasibility of choking off terrorist finance in this way.

Much of the money used in terrorism is simply carried in cash, and never enters the banking system at all.

Other money movements are off-the-books, with the financial paper trail originating or concluding in legitimate accounts in a jurisdiction - say, a developing country - where most business is done in cash in any case.

And some - especially in South Asia, China and the Middle East - use trust-based, informal systems known as hawala (India), hundi (Pakistan, Afghanistan) or chop (China), with a bare minimum of paperwork.