By Bill Neely
Basra, southern Iraq
Saddam Hussein's Iraq was a state of terror, and the security apparatus was at the heart of it.
As I walked into the secret police headquarters in Basra - which is now in British hands - I met former inmates and ordinary Iraqis had been terrified to come here until now.
What was to follow was a horrific education in terror.
The secret police building is now a bombed out shell
In the smoking basement of the bombed building was a warren of cells where prisoners had been tortured.
"People died, people were imprisoned without trial," one man told me.
We went further down, to cells that had no light and little air. They were covered with cockroaches and filth - and on the ground I saw a gas mask and bottles of chemicals.
One man said he had spent eight years inside, just for attending Friday prayers. He prayed too much and was seen as a dangerous radical.
But the secret police headquarters had more horrors to reveal.
One man whose relatives had been killed here said they had their hands tied behind their backs, and were left to hang from their arms for days on end.
Saddam Hussein controlled Iraq through fear, torture and execution. It happened here to tens of thousands of Iraqis deemed dangerous by the secret police.
A man cowered for months, crammed with 300 others into a huge cell.
Former prisoners showed how they were interrogated
Hameed Fatil told me he was tortured, along with his two brothers who were executed, and re-enacted their ordeal.
Security officers kept record of prisoners. Their fingerprints are all that is left of them - apart from photographs of their interrogations.
To call all this a chamber of horrors is a cliche - and this place is beyond cliche. The hundreds or thousands that died here and were given no trial, no voice, cry out.
On the ground I found a book called the Psychology of Interrogation, as if the men who worked here needed a handbook.
On my way out I was glad of the fresh air and glad to leave - glad that I could.
No one knows yet whether the new Iraq will be the kind of place where children can grow up free of the fear, the horror of torture.
- This is a pooled report by Bill Neely of Independent Television News.