In his first Downing Street press conference since the death of scientist Dr David Kelly, Mr Blair refused to field questions about either the late weapons scientist or the judicial inquiry into why he took his life.
"Let the judge do the judging," he said, as Lord Brian Hutton heard from his last batch of witnesses at the Royal Courts of Justice before adjourning until September 15 to ponder the evidence so far.
Mr Blair acknowledged: "It has been a tough time for obvious reasons." But he flagged his intention to stay in office and forge ahead with a pressing domestic agenda, saying: "I carry on doing the job because I believe in what I'm doing."
Dr Kelly's body was found on July 18 in woods near his Oxfordshire home after his employer, the Ministry of Defence, exposed him as the source of a May 29 BBC report alleging that a September 2002 dossier on Iraq and weapons of mass destruction had been "sexed up" to bolster the case for war on Saddam Hussein.
In particular, the BBC report suggested the dossier's most sensational claim that Iraq could deploy chemical or biological weapons in just 45 minutes was inserted despite reservations in intelligence circles.
Downing Street vigorously denied the "sexed up" claim, triggering an unseemly row with BBC executives and a particularly tough grilling of Dr Kelly by a parliamentary committee just days before he took his life.
Mr Blair went before the inquiry last Thursday, telling Hutton that he took responsibility for events leading to Dr Kelly's death, but denying the case for a showdown with Saddam's regime was embellished. If that had been true, he said, he would have resigned.
In testimony yesterday, Olivia Bosch, a think-tank associate of Dr Kelly related his description of a meeting he had in May with Andrew Gilligan, the BBC radio defence reporter who aired the "sexed up" report.
She said that, in a conversation with her, "he said he was taken aback by the way Andrew Gilligan tried to elicit information from him" with a "name game" to figure out who might have embellished the September dossier.
"The first name he (Gilligan) mentioned, and very quickly, was Campbell," she said, referring to Alastair Campbell, Blair's aide who last Friday announced his resignation.
Ms Bosch, a former UN arms inspector now with the Royal Institute of International Affairs, said Dr Kelly told her that he replied to Mr Gilligan by saying: "Maybe".
Her impression, she said, was that the way Gilligan questioned Dr Kelly "didn't give David time really to think about what was going on in that way".
Tom Mangold, a journalist and friend of Dr Kelly, testified that he discussed the 45-minute claim with him in the wake of the BBC report, and they both thought it was "risible".
"He did not feel that weapons would be deployed or activated within 45 minutes," said Mr Mangold, adding that he understood the claim to refer to the communication of an order to deploy and not deployment in itself.
On Wednesday, retired Ministry of Defence intelligence expert Brian Jones told of concerns among colleagues that assessments of the production of chemical weapons by Iraq were being "over-egged" or exaggerated.