Panorama's Jane Corbin reports

In the forbidding building of the National Monitoring Directorate security men were waiting to escort me along a dim corridor.

A portrait of Saddam Hussein stood in one corner.

It was the first time the woman dubbed "Dr Germ" and even "toxic Taha" had ever agreed to be interviewed.

It is our right to defend ourselves Dr Rihab Taha

Dr Rihab Taha was head of Iraq's biological weapons programme for seven years, until 1995.

And she is top of the list of scientists the UN team want to interview.

I asked her if she was ashamed of her past work.

"No, not at all," came Taha's answer. "Iraq has been threatened by different enemies, and we are in an area which suffers from regional conflict. It is our right to defend ourselves."

Liver cancer

While she acknowledged research and development into biological agents, she insisted the regime never weaponised the bacteria it developed.

"We never intended to use it," she continued. "We never wanted to cause harm or damage to anybody."

But the facts are undeniable. Dr Taha's team grew 19,000 litres of botulinum toxin, a food poison that swells the tongue and suffocates its victim.

Two thousand litres of aflatoxin were produced, which causes liver cancer. And they also prepared gas gangrene, which causes skin to melt away.

UN weapons inspectors discovered munitions filled with these agents dumped in a river, proving they had indeed been weaponised.

Hiding weapons

Dr Taha studied plant toxins at the University of East Anglia, between 1980 and 1984.

She had been sent by the regime, like others, to gain the expertise which Saddam intended to harness for military purposes.

She would become extremely emotional and cry to put us off the scent Former UN weapons inspector

By 1991 she was responsible for three of the country's major bio facilities and was responsible for transportation, concealment and deployment of munitions.

She married General Amer Rashid who became the man in charge of liaising with UN inspectors after the Gulf War. He was later appointed Iraq's oil minister.

For years Dr Taha insisted her work at the al-Hakem laboratory was veterinary science for civilian purposes.

"She would become extremely emotional and cry to put us off the scent," one former inspector remembered.

Deadly poisons

When a son-in-law of Saddam Hussein defected in 1995, the UN learned the truth about what was going on at al-Hakem.

But they have been unable to account for 8,500 litres of anthrax and large quantities of growth medium to culture germs.

The al-Hakem laboratory was destroyed by the UN

And there has been no definitive answer to the question of whether Iraq has developed viruses such as smallpox and haemorrhagic fever.

The inspectors want to talk to Dr Taha about small-scale biological production she is believed to have pioneered after the destruction of al-Hakem.

Intelligence sources believe small stocks of agents are held in laboratories hidden in lorries and trains.

An Iraqi defector recently told Panorama that he fitted out special "clean rooms" for biological weapons manufacture, describing filtration systems and confirming "everything is mobile now".

In the event of war, the labs could produce large stocks of agents to fill munitions.

These could be used against Western forces or even the Iraqi people if an uprising threatens the regime.

Missing anthrax

Dr Taha said she works as a consultant to the National Monitoring Directorate, carrying out administrative work and writing up old research projects.

She denied doing any work on pathogens now.

We have been very transparent Dr Rihab Taha

She did help the ministry compile the biological section of the Iraqi weapons declaration, intended to rebut US and British charges that Iraq is hiding forbidden weapons programmes.

Dr Taha rejects Hans Blix's assertions that there are gaps in the document, notably a failure to account for missing anthrax.

"We have been very transparent... It's just psychological propaganda to throw doubt on Iraq."

She was vague on why the UN and Iraqi accounts do not agree, saying that the inspectors calculation of the amount of anthrax they produced is unrealistic.

Threats

"Would you speak to the Inspectors privately?" I asked Dr Taha. "No I do not trust them. It is better to have witnesses," she replied.

I watched the Iraqi officials present at the meeting writing down her words. It was impossible to tell from her neutral tone what her true feelings were.

US Secretary of State Colin Powell spoke of intelligence which indicated Iraqi scientists had been warned of serious consequences if they revealed any sensitive information.

And according to Mr Powell, a false death certificate was issued for one scientist while he was sent into hiding. Other experts have been placed under house arrest.

Deputy Prime Minister Tariq Aziz shrugged off these accusations, insisting: "They are free people."

Rumour and fear

I knew Dr Taha had no choice but to repeat the denials. And I knew she had worked on terrible scenarios of mass murder in her laboratories.

But I felt a twinge of apprehension for her, whatever she had done.

There were rumours her estranged husband was in trouble for daring to argue with Saddam Hussein that Iraq should come clean with the UN.

A few days ago, I received a call. A Kurdish newspaper was reporting that Dr Taha had been murdered. The report alleged it was to stop her confessing what she knew to inspectors.

An Iraqi official denied this, calling the report "shameless propaganda".

In the murky pool of rumour, propaganda and fear that swirls around Baghdad, there is no way of knowing where Rihab Taha is now and what secrets she still protects.

Panorama: Chasing Saddam's Weapons was broadcast on Sunday, 9 February 2003 at 2215 GMT on BBC One.