Try as he might, Robin Cook cannot give credence to his vast lies - how does he explain away the deaths of 200 Iraqi children every day?

The facts of Iraq's epic suffering are now unassailable. The latest report by Unicef says that half a million young children have died in eight years of economic sanctions. That represents almost 200 deaths every day. Without in any way mitigating Saddam Hussein's tyranny, Unicef says: "The Iraqi people would not be undergoing such deprivation in the absence of the prolonged measures imposed by the Security Council and the effects of war." The liability of the Security Council, said the French ambassador to the UN, was "indisputable". Denis Halliday, the UN's Assistant Secretary General, resigned rather than administer "an immoral and illegal" policy. His successor as the senior UN humanitarian official in Iraq, Hans von Sponeck, followed him in despair, along with the head of the World Food Programme. Few doubt that sanctions would have been lifted long ago were it not for the intransigence of the United States and Britain.

Last week, the New Statesman published a reply by Robin Cook to my catalogue of Foreign Office lies about Iraq.

Cook's reply fails to engage with any of the points raised. It is lying to get out of lying. For example:

Cook: "The humanitarian programme is entirely unconditional . . . There is nothing to prevent Iraq ordering more medicine."

Fact: A billion and a half dollars' worth of vital supplies to Iraq is currently blocked by the UN Sanctions Committee, including food and fifty million dollars' worth of medical supplies. The supply of 16 heart and lung machines has been blocked for six months. British ministers rigidly enforce a ban on vaccines for children (Hansard, 21 December 1999). Professor Karol Sikora, the former head of the World Health Organisation cancer programme, reported: "Requested radiotherapy equipment, chemotherapy drugs and analgesics are consistently blocked by the US and Britain."

Cook: "There is no limit on Iraqi oil sales to pay for [the humanitarian programme]."

Fact: There is an effective limit imposed by the US, which has blocked contracts for vital oil industry parts already approved by the Security Council.

Cook: "Under [UN Resolution] 1284, most humanitarian contracts will be handled by the UN Secretariat without reference to the Sanctions Committee."

Fact: On 27 January, the US State Department warned that, if the UN Secretariat tried to speed up humanitarian supplies, "95 per cent of all cases [will be placed] on hold".

Cook: The bombing of civilians by American and British aircraft is an "Iraqi line" that "fabricates claims of death and destruction".

Fact: The UN Security Section regularly reports on the bombing of civilians, using UN sources. In one five-month period, 41 per cent of all strikes resulted in civilian casualties. The targets included fishermen's wharves, villages and livestock. On 30 April last year, the UN reported: "Allied war planes carried out several sorties over Ninewa Governate. The jets fired four missiles at Bashiqa area . . . seven civilians were killed. A shepherd and six members of his family [and] 101 livestock. UN team visited on 2 May." This was personally verified by the chief UN humanitarian co- ordinator in Iraq.

Cook's reply was drafted by his officials, notably Jon Davies, who heads the Iraq desk and gives candid "off-the-record" briefings. Compare Cook's lauding of Resolution 1284, "a British initiative", with Davies's private assessment to a colleague of mine that it "changes nothing whatsoever". One truth for them, another for the public.

An especially shameful example of Foreign Office deceit and panic is a letter currently being sent to MPs and members of the public, signed by Peter Hain, the junior FO minister. It sets out to devalue the scale of suffering in Iraq by implying there are "serious doubts" about the Unicef report - when there are none. It also suggests that malnourished children are merely a showcase for foreigners: a smear that further diminishes Hain. The rest of his letter is largely falsehoods. It says the "no-fly zones" in which the bombings take place are "entirely lawful". In fact, they are a Washington invention, were never ratified by the UN and have no basis in international law.

Cook wrote that: "[Pilger] denied me the opportunity to reply in his recent television programme Paying the Price." Cook was offered a major interview with most of the questions supplied beforehand. For six weeks, his officials squirmed with embarrassment as he refused even to reply. They told us of his fear of "being in a film with dying babies" and of being "skewered" in a "taxing" interview. After two months of this, they came up with a "format" whereby Cook would have an exclusive screening of the film, then give an interview "as live", restricted to ten minutes, all of which we would have to use. It was an offer designed to be rejected by any self-respecting journalist. To MPs, he misrepresented his outrageous demand as a "right of reply" required by the broadcasting regulations - yet another falsehood. His behaviour is no more than a reflection of a cowardly policy that punishes tens of thousands of small children for the misconduct of a dictator.

Last week, Cook wrote to Tam Dalyell MP: "I am entirely happy to debate the merits of our policy on Iraq." On 6 May, both Halliday and von Sponeck will be in London, speaking at Kensington town hall. I have written to Cook, asking him to make good his promise and debate with them. Watch this space.