Tom Denning, former Master of the Rolls, was not blind to his own talents, and insisted on sitting on the bench until he was 83. "Denning's law is, I hope, good law," he liked to say. And, no doubt, until he was aged about 70, Denning's law was, for the most part, good law indeed.

He was the Master of the Rolls, for example, who insisted on the rights of a deserted wife to continue occupying the matrimonial home. Here was an area where the law was an ass, and Denning rejoiced in saying so. He was the champion of the small man, and small woman, against the Big System. An encyclopaedically knowledgeable reforming lawyer, he saw it as a very simple principle that common law should protect and help the common man. Many of his summings-up, both as an Appeal Court judge and later as Master of the Rolls, have passed into legal history for their brilliance and, above all, their fairness.

But, of course, this old countryman with a face like a Ribstone Pippin and a voice like Jane Austen's Hampshire accent (Beryl Bainbridge wouldn't have approved) was given 100 years to live, rather than the scriptural three-score years and ten.

Had he died aged 70, Denning would have gone to his grave with an unblemished reputation as one of the great libertarians of English history. The fact that he was a show-off, or that he derived obvious, puritanical, salacious delight from presiding over the inquiry into the Profumo scandal would have been regarded as harmless peccadilloes. Had he died at 70, we'd not have heard the Denning who thought black men shouldn't be allowed to sit on juries. To say that he lived too long is not merely to suggest that in extreme old age he became increasingly intemperate in his views. He was perfectly entitled to do that. Rather, it is to say that if you live 100 years many of the things which you regarded as virtues in your youth will have become vices in the eyes of your younger contemporaries by the time you die. Supposing that some of your historical heroes had been granted the gift of eternal life. Imagine having lunch today with Mrs Pankhurst, or Keats, or Thomas Jefferson. Might you not discover that you were shocked by their taking certain evils for granted - racial segregation, say, or corporal or capital punishment?

This is the lesson which I learnt on that fateful summer day a decade ago when I was sent off by the Spectator to interview Lord Denning in Whitchurch, Hampshire, the small town where he, his brother the Admiral and his brother the General had all been born above their father's draper's shop. I am not by nature a newshound, and I have conducted only a small handful of interviews in my life. It was certainly not my intention to write anything "controversial". My intention was to write 1,000 words of praise for the dear old champion of Liberty, with, perhaps, a few anodyne memories of pre-First-World-War Hampshire.

Sensing this, perhaps, Denning, who was nothing if not a headline-grabber, started to say things that were calculated to be "talking points"; MASTER OF ROLLS DENOUNCES ARCHBISHOP was his first bid to shock. He told a story of some private individuals, "ordinary churchgoers", a married couple who had come to Denning with a bee in their bonnet, about some Disgusted of Tunbridge Wells issue. I forget if it was Women Priests, Gay Clergy, or something else. Digging around in the law books, Denning advised them to take out a private action against the Archbishop of Canterbury. His lawyers, doing their job, defended the case and bled Denning's friends dry with costs. Indeed, I think the end of the story was that they were cleared out of their house and their life savings.

Some people listening to this tale would have thought it showed Denning in a poor light. "It's entirely wrong to use costs as a weapon in a case like that," he kept saying. But as an experienced judge, he could have foreseen that this was what would happen. If anyone were to blame for the ruin of his friends, it was Denning himself.

Seeing that I made no notes during this anecdote, he leaned forward towards the tape recorder and began, slowly and deliberately telling the machine that the Guildford Four should have been sentenced by a jury of Twelve Good Men of Hampshire to be hanged. "Then we should have forgotten all about them."

It was this view - surprising, to say the least, in the light of all we then knew about the miscarriage of justice that had occurred in the Guildford case - which lit the touch paper. As an encore, Denning the Europhobe told me that it was "entirely wrong" for this country to have put its interests in Europe into the hands of "a German Jew, if you please" called Leon Brittan.

When I questioned the accuracy of this description of Sir Leon, Denning reaffirmed it: "Look him up - you'll see he was a German Jew." He added that Brittan had been a lousy libel lawyer and that it was only those who were duds at the Bar who went into politics. (Tony Blair note well.)

There followed the predictable rant. Seas and oceans that we had known to be British waters since the time of Sir Francis Drake were now "Spanish waters, if you please"....

Well, Denning got what he wanted. The Spectator article caused some of the Guildford Four to consider suing him. Sir Leon Brittan was hurt and angry. Denning came on the six o'clock news saying that he had been quoted out of context. He even invented a new law for the occasion, claiming that I had inveigled him into libelling himself. Lady Denning and others expressed their disgust that a journalist from London should have taken advantage of a poor old man. Denning's reputation was never quite the same again.