Sir Michael Parkinson's dad was so wonderful that every day before he went down the pit, come blizzard or hurricane, he'd rescue two drowning toddlers from the village pond, pluck a stranded kitten from out of the village tree, give the village scallywags a firm but fair clip round the ear, then come home briefly to the Parkinson shoebox to help the Labour Party write its manifesto for the new NHS while supervising rehearsals for the colliery brass band.

The Greatest Living Yorkshireman doesn't actually say this in his bestselling Parky: My Autobiography, but I think we can safely take it as read. Parkinson idolised his coalminer father Jack, once crying for a whole hour over a photograph he found two years after the old man's death.

Jack, Parky claims, was a man "full of life and laughter". He was poor but happily so: "He would say: 'If you don't have money, you never miss it.' He didn't care." Every day, Jack would walk three miles to Grimesthorpe Colliery where he'd spend eight hours underground and earn seven shillings a shift. But he wanted better for young Michael, who went to grammar school, got a job on the local newspaper and through hard work, bluff Northern charm and sheer, uncompromising ruddy genius eventually became the greatest chat show host in the land.

But now one of Parky's cousins is telling a different story. If Jack was a saint, claims Michael Tonge, in a pamphlet produced for his relatives, it was very much of the plaster variety. The real Jack, he says, was "bombastic, arrogant, interfering, grumpy, selfish and money-grabbing". And he apparently wasn't even a great miner. "I've spoken to some old miners. They told me he was not a good deputy to work for. They said he was a hateful man... I cannot find anyone who will give him a good name."

Parky is furious. So furious that he has threatened to sue both Tonge and the newspaper that reprinted his allegations, the Barnsley Chronicle. (The very same paper where Michael first honed his journalistic art after leaving school.) Tonge is reportedly defiant: "I'm not worried about legal action... I won't be consulting a solicitor because I haven't got one."

Poor Parky: it surely can't be pleasant for so distinguished a figure to have his version of reality challenged by a redundant glass factory worker. On the other hand, to paraphrase Oscar Wilde on the death of Little Nell, it's the sort of story that requires a heart of stone not to burst out laughing.

Perfect though Parky is in so many diverse ways, it cannot have escaped the notice of even his most ardent fans that the man's self- mythologising tendencies border on the idolatrous. To listen to Parky hold forth sometimes, you would imagine that he was the only journalist ever to have turned a half-way decent sentence; to read him on the art of interviewing celebrities, you'd find it surprising that Jonathan Ross and Graham Norton hadn't yet been executed by firing squad for their temerity in diverging so outrageously from the Master's one true style.

"I am not interviewing war criminals or paedophiles. I'm interviewing people whose only crime is to entertain people," he once thundered when accused of being unduly deferential to his guests. But there are quite a few of us who would like to know a little bit more about our favourite celebrities than is vouchsafed by Parky's "So tell me, Sir Paul McCartney, when exactly did you start being quite so amazing?" interrogation technique.

A journalist's first duty is to the truth. Parky ought surely to have realised that by now. And if he hasn't, maybe that cousin has done him a favour. Calling a spade a spade. It's what Yorkshiremen are supposed to do. So what, exactly is Parky's problem?