Charles Clarke to appear on Newsnight

Charles Clarke is going to be on Newsnight tonight to begin his post-sacking rehabilitation. Apparently in his interview he says that the "suggestion that from July 2005 I had personally known about the failure to consider deportation and done nothing about it was wrong... As others have already made clear to the committee, it was only in late March 2006 that ministers, including myself, were made aware of the failure to consider for deportation some foreign national prisoners at the end of their sentence, and when we were aware of this action was then taken."

If it's true that Clarke really didn't know until March, why did he not go to the House and make a statement when he found out?