Feeble excuse?

Following on from yesterday's post, the Home Secretary has said that he would be "breaking the law" if he intervened to prevent Mr McKinnon's extradition to the United States to stand trial in respect of his computer hacking activities. Ignoring for the moment the fact that a law which has been made by Parliament can always be unmade by Parliament, the question which immediately springs to my mind is - whatever happened to the Royal prerogative?