By Paul Reynolds BBC News Online world affairs correspondent

An index to the 12,000-page Iraqi weapons declaration is the gateway to a labyrinth.

But investigators will have to search through it as they try to find out if Iraq has been truthful in denying that it has weapons of mass destruction.

Specific intelligence information might have to be provided by the United States to weapons inspectors if proof is to be uncovered Gary Samore, IISS

The index makes references to "former" nuclear, chemical and biological warfare programmes and has sections on the "status" of current developments in these fields, which Iraq has said are no longer connected with weapons.

There is also a section, as required, on ballistic missile development.

The actual declaration has not been released. According to Gary Samore of the International Institute for Strategic Studies in London (IISS): "It could be weeks before people can go through it. It will be a long process."

Dr Samore, who helped to compile the IISS's own study of Iraqi weapons earlier this year, said that if Iraq had anything prohibited, it was "most likely to be the stockpiling of chemical and biological agents which are easiest to hide".

This document might not be of much use in tracking them down and, said Dr Samore, "specific intelligence information might have to be provided by the United States to weapons inspectors if proof is to be uncovered".

'Plants of concern'

The document is in four parts, corresponding to the demands for statements on Iraq's nuclear, chemical, biological and missile programmes laid out in Security Council resolution 1441.

The index lists sites in which nuclear, chemical and biological weapons were made and adds sections on what the role of these and other sites are now.

Some of the sites were listed as "plants of concern" in the British Government and CIA dossiers on Iraq, which accused Saddam Hussein of developing weapons of mass destruction.

Among these are the Fallujah 2 chlorine and phenol plant and the Fallujah 3 pesticide plant.

The index hints at some interesting information about foreign suppliers

The weapons inspectors and the US and British governments will also be looking for information about material, especially chemical agents, which were unaccounted for when the inspectors left Iraq in 1998.

Information about this is regarded by the US and UK as a test of Iraq's credibility.

There appears to be no direct reference to this in the index though it could be contained in the text.

On the other hand, a senior Iraqi official has already said that there are no new documents relating to the unaccounted-for material. This issue alone could provoke a crisis with the United States and Britain.

Foreign suppliers

The index hints at some interesting information about foreign suppliers. One annex promises 11 pages of "Procurements of the (nuclear) Design Centre".

The first section - a 2,081 page declaration on its nuclear bomb programme up until 1991 - helps explain why the United States, supported by the other four permanent members of the Security Council, made a grab for the document when it arrived at the UN in New York.

The nuclear declaration appears to contain details of how Iraq was trying to make a nuclear bomb. For example, "Techniques and processes associated with electromagnetic isotope separation" are mentioned.

The dissemination of this kind of material to non-nuclear states is outlawed under nuclear non-proliferation agreements.

It is also the case, though, that Washington wanted to get on with the job quickly itself and would not wait for the weapons inspectorate Unmovic to take a first look.

Ballistic missiles

The missile section refers intriguingly to "Summary of the programme for ballistic missiles with a range greater than 150 kilometres".

Whether this is a current programme remains to be seen. If it is, it would violate UN resolutions under which Iraq cannot have rockets with a range of more than 150km. It could refer to the earlier Scud development.

Iraq also seems to be admitting to a programme to turn fighter jets into unmanned aerial vehicles. The US and UK say that this was for chemical warfare.