Claims about WMD 'may have been excuse rather than reason for war'

One of Britain's most senior former military intelligence chiefs said it was "unacceptable" for Tony Blair to rely on a single source for the controversial claim that Saddam Hussein could deploy chemical and biological weapons within 45 minutes, new documents to the Hutton inquiry show.

In perhaps the most scathing criticism of Mr Blair by a former officer, Air Marshal Sir John Walker, a former chief of Defence Intelligence, suggested the Government's claims about Iraqi weapons of mass destruction were "not the reason to go to war, but the excuse to go to war".

Sir John, who served as deputy chairman of the Joint Intelligence Committee (JIC), the body that drew up the September dossier on Iraq, also queried whether normally cautious intelligence procedures had been changed.

His concerns were revealed in a letter and note to MPs investigating claims that the government dossier had been "sexed up" to exaggerate the dangers posed by the Iraqi regime. The documents for the Foreign Affairs Select Committee, which have until now never been published, show that Sir John shared the concerns of his former colleagues in the Defence Intelligence Staff (DIS) about the dossier.

The Hutton inquiry has heard that two members of the DIS, together with another official who described himself as "the most senior" British intelligence expert on WMD, complained about the way intelligence was being used last September.

Sir John, who served as chief of Defence Intelligence from 1991 to 1994, oversaw reforms of intelligence procedures after the Scott inquiry into the arms-to-Iraq affair. In his letter, Sir John is highly critical of the fact that the "45-minute" claim was given such prominence even though it came from a single source.

"It was the immediacy of the WMD threat that convinced some MPs to vote with the Government on the crucial division on taking the country to war," he wrote. "As an ex-deputy chairman of the JIC and chief of Defence Intelligence, I cannot credit that an assessment on which such an awesome decision rested should be based on a single source. I find that inconceivable. I also find it unacceptable"

In his note to the committee, written on 2 July, Sir John suggests that the change in the no-fly zone operations from defensive to offensive tactics last autumn was because the US and UK had already decided to "prepare the battlefield" by removing threats such as Iraq's Silkworm missiles. "It points to a question that needs to be posed," he wrote. "When was the decision taken to go to war? If this thesis bears examination, then the nation was committed to war in the late summer, early autumn of 2002."