Three years after leaving Sanctuary Buildings, David Blunkett's remarks to me about Charles Clarke, in interviews for my new biography, show that he has still not lost the capacity to send a shockwave through the world of education: "I thought Charles would have developed more."
Under Clarke, he says, the education team have "taken their foot off the accelerator. They've gone soft." The evidence, he says, is in the bland, consensus-pleasing style of certain recent initiatives. "They've produced documents called Excellence and enjoyment," he scoffs. "The next one will be called Smiley and fun."
Blunkett's professional relationships were equally combative during his time as education secretary. Indeed, the relationship between the Department for Education and Employment (as it then was) and Number 10 has been caricatured as a battle with the Prime Minister's policy unit - specifically, with Andrew Adonis, then Blair's education adviser.
Much of the difficulty arose from Blunkett's determination not to be pushed about - to be clearly and unambiguously in charge of education. Adonis was often referred to in the press as "the real education secretary". Such a description - although inaccurate - was almost tailormade to rile Blunkett, the more so given that both were, in their different ways, close to Tony Blair.
On many issues Blunkett and Adonis were as one: in the development of city academies, for instance, which David Blunkett championed and persuaded sceptical Labour MPs to support despite much opposition from Labour-led local education authorities.
But there were also genuine, stark theoretical differences with Adonis, notably over the role of LEAs, which he was keen to pare back (as had been Stephen Byers in his tenure as schools minister), and selection, about which he was far more relaxed than Blunkett.
So there was certainly tension, with Number 10 tending to feel that Blunkett was dragging his heels and not reforming fast enough, but it generally took the form of a negotiation rather than a confrontation.
Much of the tension came from what Blunkett and his advisers saw as Adonis's alliance with Chris Woodhead, whom Blunkett would have preferred not to have kept in post as chief inspector of schools.
One adviser argued that "there were times when Andrew was his own man, and there were occasions when you could just see Chris behind him; the two had clearly been speaking". Blunkett and his advisers talked of the "Adonis-Woodhead alliance". But far from agreeing on everything, Woodhead thought Adonis was all talk and little real action, and Adonis would often despair at Woodhead's abrasiveness.
They did, however, need each other politically. Without the support of Number 10, Woodhead would not have been kept on in 1997, let alone been allowed any influence on policy. Moreover, without Woodhead, Adonis and Number 10 would have had to be far more confrontational with Blunkett - Woodhead acted as a lightning conductor for the anger.
Blunkett felt that Woodhead had decided not to co-operate but to fight - a cardinal sin in Blunkett's book. Nevertheless, Woodhead was certainly useful at times. Ofsted had begun to arrest decline by identifying failure but it was not, in Blunkett's view, Ofsted's - or Woodhead's - job to deal with the problems. That remit, Blunkett felt, was his own.
Woodhead was not backwards in proclaiming when he believed himself to be right, both inside the department and in public. A critic within the Department for Education and Employment recalled one meeting at which Woodhead reacted to a contribution by Michael Barber (then head of the department's standards unit) by "putting his feet up on the table, stretching and yawning. His body language made it clear what he was thinking: 'why are we having to listen to all this rubbish?'"
What Blunkett saw as Woodhead's refusal to play ball, Woodhead saw instead as Blunkett's refusal to engage with him. Blunkett had lived with the confirmation in 1997 that Woodhead would remain in post. He was, however, determined that Woodhead's contract would not be renewed when the time came for re-appointment in 1998. Number 10, however, thought differently.
Woodhead's re-appointment was the only clear Whitehall defeat for Blunkett in his time at the DfEE. Adonis, via Blair, won, with the PM ordering Blunkett to keep Woodhead. As one close adviser put it: "David went ballistic. I have never heard him swear so much. 'What is the bloody point of my being here?' he screamed. 'Who is the education secretary, me or Adonis?'. Even to the civil servants, he never made any bones about the fact that he had been put in an impossible position."
The real education secretary was always Blunkett. But like any Cabinet minister, sometimes he was forced to compromise. That remains as true of his time as Home Secretary as when he was education secretary.
David Blunkett by Stephen Pollard is published by Hodder at pound;20