The documents from the Cabinet Office and Foreign Office suggest that in March 2002 Mr Blair was concerned primarily about regime change rather than, as he subsequently said, weapons of mass destruction. Invasion simply for regime change would have been contrary to international law.
The Foreign Office yesterday acknowledged the documents were genuine but stressed they were only a snapshot of thinking at a particular time. Nor did they reflect the changes that took place over the following 12 months, in particular referring the issue to the UN, which the White House did at Mr Blair's behest, though it failed to get a second security council resolution authorising war. -------- "Leaks cast doubt on PM's motive ," Ewen MacAskill and Michael White, Monday September 20, 2004, The Guardian
"I haven't seen anyone post the quote from Blair, but you may be referring to the Guardian newspaper's assertion that the Foreign office said the docs were authentic. Who in the Foreign office said it is not mentioned."
Using "The Foreign Office said" indicates that it is an official on-the-record comment from a Foreign Office spokesman. I imagine the American media would use "The White House said.." in a similar manner.
Note that the confirmation that the documents were genuine is from September of last year. Like I said before, this is in no way a new story.