By Jon Silverman Legal Affairs analyst

That a multi-billion dollar lawsuit is one of the delayed consequences of the 11 September attacks ought to come as no surprise.

The United States is the home of the class action, in which groups of claimants, sometimes hundreds-strong as in the case of Holocaust survivors and their heirs, seek compensation in the courts for a perceived grave wrong.

Over the past decade, the defendants in such actions have frequently been based outside the US - among them Swiss banks, German industrial giants and Japanese corporations.

But it is comparatively rare for a foreign government to be cited in a suit and a successful outcome will not be easy to achieve.

Not concluded

The lawyers say the suit is closely modelled on the civil action taken against the Libyan Government for the destruction of Pan Am Flight 103 over Lockerbie in 1988.

As with Lockerbie, keeping the atrocity in the public eye is a key motive

But although lawyers representing the claimants issued a press release in May 2002 announcing that Libya had offered to pay $2.7 billion (�1.8 billion), it subsequently appeared that the deal had not been concluded.

It may be some time, even years, before the full amount is paid.

In the 1990s, in response to the growing problem of international terrorism, the US Congress passed a law which, in theory, allowed for foreign states, designated as sponsors of terrorism, to be sued in the US courts.

Sudan is currently on the list of ''pariah'' states. However, establishing to the satisfaction of a judge that Sudan was connected to the 11 September attacks may be beyond even the most skilful of lawyers.

Political agenda

The position of the Saudi royals named in the lawsuit is even more complicated.

Named in lawsuit: Saudi defence chief Prince Sultan bin Abdul Aziz al-Saud

Although the Bush administration is conducting efforts to freeze the assets of organisations - businesses and Islamic charities included - which can be shown to support terrorism, it has strong political reasons for not wishing to alienate a Saudi regime always considered a key ally in any coalition against Iraq.

But for the wider world, if there is compelling evidence, as the lawyers indicate, that money flowed between the Saudis and al-Qaeda, then testing that evidence in a transparent forum, such as a US court, must be a good thing.

The families of those who died on 11 September are to receive compensation under a government-funded scheme in any case.

But precedents such as Lockerbie suggest that money is not the real object of lawsuits.

It is a cause to pursue and a way of keeping the atrocity firmly in the public eye.