Robert Jackson is a natural, quixotic rebel but an unlikely turncoat. Somewhat of the absent-minded professor type, he is urbane, erudite, courteous and charming. I once travelled with him on a parliamentary delegation to Namibia where I saw at close quarters a thoughtful, kindly man who was rarely given to political risk-taking or dramatic gestures.
Although well to the left of the average Thatcherite, he seemed to fit in well with the historic broad strand of "One Nation" Toryism that still had a central role in the fabric and structure of even Mrs Thatcher's party - albeit not necessarily at the policy-making level.
He had always been a pro-European, coming to Westminster from a term in the European Parliament, but he was enough of a team player to be regarded as the classic example of a competent MP capable of "balancing the ticket" when it came to recruiting an equal number of "wets" and "dries" to the junior ministerial ranks. Even after he left ministerial office and became disappointed with the subsequent direction of the Tory party, he conducted his disagreements with the utmost civility. Whips were slow to chastise as his views were usually based on deeply held principles.
Mr Jackson does not enjoy the limelight but the effect of his 15 minutes of fame will have a greater impression on the public image of the Conservative Party than Michael Howard is prepared to admit. Mr Howard is right that, come the general election, this defection will have long since become yesterday's news. But that the defection traffic, with a general election only some 15 weeks away, is still from Tory to Labour indicates just how irrelevant to the national political debate the Tory party is.
Many will accuse Mr Jackson of the ultimate betrayal. The suspicion will be that, having enjoyed 22 years at Westminster under the Tories, he is making a cynical attempt to book a passage into the Lords. This charge has already been made by the Tory MP Julie Kirkbride. I doubt, however, that - even if Mr Jackson ends up eventually in the Lords - this was his original motivation. He has been out of sorts with the party for several years and this is evidenced by his decision to announce, almost immediately after Iain Duncan Smith became leader in 2001, that he would not stand for re-election in Wantage.
Others will worry that Mr Jackson's departure may presage a bloodbath even before, and certainly after, the expected May election with further defections. I doubt that will happen, but the message this defection sends out is that many former Tories feel that Mr Blair is just as good a conservative as anyone - without the opprobrium that goes with the label.
Mr Jackson's most damaging claims are of Mr Howard's opportunism and the description that the Tory leader "only has two registers: one is scorn and the other is anger". These will be milked mercilessly by Labour in the run-up to the election, even though Mr Jackson will by then have disappeared without trace.