Three years after invading Iraq, George Bush and Tony Blair are still dipping into the trough of deception and disinformation that launched the war: hailing non-existent progress, declaring sanctimonious satisfaction with sectarian elections and holding out the mirage of early withdrawal. In reality, the occupation and divide-and-rule tactics have spawned death squads, torture, kidnappings, chemical attacks, polluted water, depleted uranium, bombardment of civilians, probably more than 100,000 people dead and a relentless deterioration in Iraqis' daily lives.

Much of this goes unreported in the British and American media, stripped of context or consigned to the small print. The headlines are reserved for Abu Musab al-Zarqawi's terrorism, Saddam Hussein's farcical trial and the perennial "exit strategy". We are fed the occupiers' spin, while words of scepticism are deemed jarring. Invited to join a popular BBC radio programme for Iraq's recent elections, I quoted George Bush's accidental brush with reality when he declared: "You can't have free and fair elections in Lebanon under Syrian occupation." An editor politely said: "Sorry Sami, but we are sticking to a positive spin on this one. I am sure we will invite you on other occasions."
A few days ago, a large-scale opinion poll conducted by Maryland University showed that 87% of Iraqis (including 64% of Kurds) endorsed a demand for a timetabled withdrawal of the occupiers. The findings were mostly ignored by the British media.

Admittedly, reports on the ground are difficult and dangerous. But while western media are not averse to revealing deceptions around the WMD scare and pre-war lies, occupier-generated news still takes pride of place, and anti-occupation Iraqi voices of all sects - particularly Shia clergy such as Ayatollahs Hassani, Baghdadi and Khalisi - are ignored.

A few months before US soldiers boasted of using white phosphorus, the BBC's Paul Wood defended his reporting from Falluja in the November 2004 siege, telling Medialens: "I repeat the point made by my editors, over weeks of total access to the military operation, at all levels: we did not see banned weapons being used ... or even discussed. We cannot therefore report their use." Doctors and refugees fleeing US bombardment talked of "chemical attacks" and people "melting to death". But for the BBC, eyewitness testimony from Iraqis is way down the pecking order of objectivity.

It would clearly be wrong to portray victims' claims as uncontested facts, but there is a duty to publish and investigate them. Had, for example, Iraqi families' claims been highlighted shortly after the occupation began, the world would not have waited over a year to learn of torture at US-run jails. It was not until US soldiers gleefully circulated sickening pictures of tortured Iraqis that the media paid attention.

Many Iraqis have persistently accused US-led forces of "controlling" an assortment of death squads or private militias and "turning a blind eye" to many terrorist attacks. Almost every week, handcuffed and blindfolded men are found lying next to one another, each killed by a single bullet to the head. Who is methodically torturing and killing these people? Who has so far assassinated more than 200 academics and scientists? Iraqis not linked to the Green Zone regime are convinced that US forces and US-backed mercenaries are involved.

Support for some Iraqi claims, however, comes from unexpected sources: two US generals have admitted the presence of targeted killing squads, and last February the Wall Street Journal let slip the presence of six US-trained secret militias. In the same month, Lt General William Boykin, the deputy undersecretary of defence for intelligence, told the New York Times: "I think we're doing what the Phoenix programme was designed to do, without all the secrecy." US death squads assassinated about 40,000 people in Vietnam before Congress halted "Operation Phoenix".

A retired general, Wayne Downing, the former head of special operations forces, affirmed that US-led killing squads started operating immediately after the March 2003 invasion. He told a bemused NBC interviewer: "Katie, it's a nasty situation in Iraq right now, and this may help it get better."

But the occupiers' "Sunni v Shia" mantra dictates the agenda and clouds the issues. The daily news intake is moulded by senior occupation forces' PR officers and embassy officials camped in the Green Zone - once Saddam's fortress, now a vast monstrosity housing the occupation authorities and their competing and corrupt Iraqi proteges of all sects.

The lie of WMD embroiled Britain in an immoral, illegal war. Disinformation about the war is the pretext for keeping troops and bases in Iraq. Cosmetic sovereignty and partial withdrawal will not convince Iraqis witnessing the completion of permanent US bases, and US advisers controlling "sovereign" ministries and planning back-door oil privatisation.

Only complete withdrawal will satisfy most Iraqis. And if genuine liberty and independence are not forthcoming, the spiral of violence will intensify from Afghanistan to Palestine.

· Sami Ramadani was a political exile from Saddam's regime and is a senior lecturer at London Metropolitan University sami.ramadani@londonmet.ac.uk