Dick Cheney, the US Vice-President and the administration's most outspoken hawk over Iraq, faced demands for his resignation last night as he was accused of using false evidence to build the case for war.
He was accused of using his office to insist that a false claim about Iraq's efforts to buy uranium from Africa to restart its nuclear programme be included in George Bush's State of the Union address - overriding the concerns of the CIA director, George Tenet.
Mr Cheney was also accused of knowingly misleading Congress when the administration sought its authorisation for the use of force to oust Saddam Hussein.
The allegations against Mr Cheney have come most vocally from a group of senior former intelligence officials who believe that information from the intelligence community was selectively used to support a war fought for political reasons. In an open letter to President George Bush, the group have asked that he demand Mr Cheney's resignation.
In a further development, it was reported in an Italian newspaper today that an African diplomat offered Italian intelligence services documents relating to Saddam's alleged attempts to buy uranium in Africa.
The report in La Repubblica, largely based on unidentified Italian secret services sources, also linked a theft at the Niger embassy in Rome during the 2001 New Year's holiday to the affair.
La Repubblica, quoting a source from Sismi, the Italian military intelligence service, said that in late 2001 or early 2002, M16 obtained the documents. The source implied that Italian colleagues provided the information to British intelligence officials.
"There were several meetings, at a higher level, almost always in London," the source was quoted as saying. "Despite this positive climate, we don't know if it was the English who passed on that stuff to the CIA. It's rather probable."
The source, La Repubblica reported, said the Italian Foreign Ministry had raised "strong objections" and "protests" about the information provided by Italian intelligence.
The paper published what it said were copies of four documents used to bolster the claim that Saddam was trying to buy uranium.
In January 2001, the Niger embassy reported a theft occurred while the mission was closed during the New Year's holiday, the paper said. Little was missing – a watch and three small bottles of perfume. Drawers were overturned, closets were opened and paper was all over the place.
As the clamour for a full inquest into the African uranium claims grew on both sides of the Atlantic, Jack Straw, the Foreign Secretary, was accused by MPs of lacking "credibility" after he admitted knowing a month before the war that documents making the assertion were forgeries. Mr Straw said in a statement he had known that letters given to the UN nuclear agency, the International Atomic Energy Agency, about the Niger claim were fake as early as February.
Mr Straw also claimed that the Government's case for military action was not based on "intelligence reports".
Labour MPs, including Tam Dalyell, the father of the House, asked why Mr Straw had not told MPs that the documents were fake in advance of the vote to approve military action on 18 March. "He now says the Government knew it was a forgery in February. Why didn't he tell us before Parliament voted for war?" he said. "Also if the case for war is not based on intelligence, what is it based on?"
Last night the Labour-dominated Foreign Affairs Committee asked Mr Straw to reveal what he knew about the Niger claim.
Donald Anderson, the committee's chairman, wrote to Mr Straw asking him when the CIA first questioned the Niger connection, and why ministers had not admitted earlier that there were doubts about the claims. The committee also asked whether the CIA had questioned any other claims in the September dossier on Iraq's weapons.
The letter, signed by 11 MPs of all parties, called on Mr Straw to confirm The Independent's report that technical documents and centrifuge parts found at the home of an Iraqi nuclear scientist in Baghdad had lain buried for 12 years. The letter also asked Mr Straw to reveal when he knew that the former US ambassador Joseph Wilson had found claims about Niger-Iraq links to be false.
Last week the White House admitted that the claim that Iraq was seeking "significant quantities of uranium from Africa" - based on faked documents provided by the Italian intelligence services - should not have been included in President Bush's speech of 28 January.
In Washington there is no conclusive proof that Mr Cheney was responsible for insisting that the claim be made in the speech. But there is clear evidence of Mr Cheney's interest in the alleged Niger deal. Joseph Wilson, a former US ambassador, said he was asked by the CIA to go to Niger and investigate the claim in a request from the Vice-President's office. Mr Cheney's chief of staff, Lewis Libby, has admitted that during a briefing from the CIA "the Vice-President asked a question about the implication of the report".
There have been reports from CIA officials that in the months before the war Mr Cheney made a "multiple number" of personal visits to its headquarters in Virginia to meet officials analysing intelligence relating to Iraq. "[He] sent signals, intended or otherwise, that a certain output was desired from here," one senior CIA official told reporters.
The CIA director, Mr Tenet, said he accepted responsibility for approving the speech but said his officers had only "concurred" with White House officials that by naming the British Government as the source of the Niger claim it was "factually correct". Britain has stood by the claim, saying it has evidence in addition to the Italian documents.