John Reid's claims that rogue elements within British intelligence have been briefing against the government have prompted renewed calls for an inquiry into the allegations.
Reid: Blames rogue elements
Opposition MPs expressed a mixture of astonishment and scepticism at his remarks.
He said that briefing against the government and intelligence chiefs had come from "one or two unnamed, unappointed, anonymous
people with uncorroborated evidence".
Conservative MP Gregory Barker asked Dr Reid on Thursday whether the security services were now conducting an inquiry to discover the source of these anonymous briefings and if any findings could be published although the minister refused to be drawn on the issue.
Mr Barker later told BBC News Online: "If SIS are not conducting their own internal mole hunt then John Reid must have been shooting from the hip and the security professionals are not taking his claims seriously."
Dr Reid's assertions came in an article in The Times and in numerous TV and radio interviews on Wednesday, including a series of exchanges on BBC Radio 4's Today programme.
Here he repeatedly criticised claims made by BBC defence correspondent Andrew Gilligan, who reported security sources had accused Downing Street of exaggerating their information in a dossier on Iraq.
Spook-bashing is all too reminiscent of the nightmare obsessions of the last days of Harold Wilson in Number 10
Deputy Commons leader Ben Bradshaw later told Channel 4 News: "I suspect that the intelligence services, as they always would, would take
any unauthorised briefing from their members extremely seriously."
But the BBC's deputy director of news, Mark Damazar, said there was no way the corporation would reveal its source.
Shadow foreign secretary Michael Ancram said Dr Reid's remarks alone made the case for an independent inquiry into the handling of intelligence.
"So serious is his attack, it cannot possibly be allowed to rest. He has
single-handedly made the case for an inquiry," he said.
Dr Reid's remarks were seized on by Liberal Democrat leader Charles Kennedy, who described them as "quite extraordinary".
He quickly raised his party's call for an independent inquiry into the WMD row up to a judicial probe.
"I think we've
now moved actually even beyond what we as a party were saying only this time
yesterday, that we wanted a cross-party select committee set up," he told BBC's Good Morning Scotland radio programme.
Campbell: Reid's comments have 'raised the stakes'
"I think we've gone beyond that as a result of John Reid's comments, and we
will have to have some form of judicial inquiry into this entire issue."
Senior Liberal Democrat Paul Tyler said: "I listened with amazement to John Reid this morning. Clearly his doctorate was in paranoia.
"Spook-bashing is all too reminiscent of the nightmare obsessions of the last days of Harold Wilson in Number 10."
Dame Pauline Neville-Jones, former head of the Joint Intelligence Committee, which oversees intelligence reports for the government, said she did not think there had been "conscious distortion" by the government.
She told Today: "In the nature of the information coming out of Iraq, we have a lot of people there who were axe-grinding - the dissident community and the people who have reasons to give information of the kind that is very difficult actually to corroborate."
Andrew Wilkie, a former senior Australian intelligence officer, claimed political pressures skewed British intelligence on Iraq.
Mr Wilkie quit the Office of National Assessments, his country's chief
intelligence agency, because he said the UK, US and Australian documents he had seen did
not justify war.
"It struck me, and I think it struck a number of people, that the assessments
particularly out of the US but to a lesser degree still out of the UK, that
the assessments were skewed by some political pressure," he said.
"I didn't go so far as to say political interference.
"I think when the day of reckoning comes I think all of the intelligence
agencies in all three countries will be responsible for at least some
over-rating of the threat posed by Iraq."