Another series of Who Do You Think You Are, the seventh according to bbc.co.uk, (BBC1, Wednesday) ought to produce a collective groan across the nation.

Genealogy made interesting. Somehow I don’t think so. The premise of this sad excuse for a programme involves a celeb of some description taking almost an hour of prime time TV to allegedly research their family tree. Invariably some kind of interesting relative is turned up in the process, producing an exaggerated reaction ranging from self-deprecating cod pomposity (Boris Johnson) to over the top angst and self-doubt (Ainsley Harriott).

Last night’s carry on involved Big Bother host, Davina McCall, weeping her way through the deeds and miss-deeds of various ancestors, apparently genuinely affected by their trials and tribulations. Some developer from Windsor several generations back gets in the financial do-do and tops himself – Davina blubs, Some French cop does well for himself, Davina blubs again, Davina meets so French relative and blubs yet again and again, and again.

Forgive me for being a tab cynical perhaps. I have nothing against shows of emotion – in fact I’m up for a good cry with the best of them. Indeed it is common knowledge that since Gazza set the trend we Geordies do very little else. However, I have great difficulty being moved to any kind of emotion for long departed family members of whom I have very little knowledge. I distinctly remember being told that my Great Grandfather died an untimely death following a roof collapse in the mine. I can’t say I was distressed. I can do a good line in self-questioning and introspection too. When I discovered that a distant ancestor called William Jobling was hung for a murder that he didn’t commit and stuck on a gibbet for his trouble it certainly seemed unfair and somewhat barbaric but I didn’t experience a second on angst over it. In fact it was all rather amusing.

I fully understand that tracing the steps of ancestors caught up in the Holocaust is likely to be tough. So I understand why Jerry Springer found his journey through central Europe emotional, but as for the rest of them, oh please! Get a grip!

What’s worse – we are expected to believe that these over paid individuals of moderate talent actually did the research themselves. “Oh look at this”, says Davina, unconvincingly surprised as she comes across an article from an ancient local paper. So far La McCall’s principal acting roll was playing the zombie incarnation of herself in Charlie Brooker’s blood drenched and brilliant Dead Set. Who Do You Think You Are suggests that zombies are pretty much Davina’s limit.

Of course the very notion that these celebs do the research themselves is risible. Not just insulting our intelligence as waving but mooning in its collective face. Suspension of disbelief shouldn’t need to be part of the documentary genre.

But one more little white lie in the plethora of lies that crowd into the average evening’s viewing is hardly the point. The real problem with Who Do You Think You Are is that I don’t actually care and what’s more it is not very interesting. The idea of researching one’s family background could be fascinating – though it makes not a jot of difference to the person you are in the here and now. But give me one good reason why I should give a monkey’s fornication about who might be the ancestor of whom, what they did for a living, whether they were a total and utter scumbag or a philanthropic saint of their era.

I assume this must be pretty inexpensive stuff or the Beeb would have canned this devastatingly dull tripe. Talk about taking the cult of celebrity beyond the grave.