How Cherie's friend cottons on to conman Foster but has door to No 10 slammed shut

A trusting interviewee with a loopy world view, a credulous interviewer, claims of betrayal over the docu-softsoap that results. Two weeks ago it was Wacko Jacko, tonight it is Crazy Carole.

The Conman, His Lover and the Prime Minister's Wife, a BBC1 film about Cherie Blair's health guru and her partner, Peter Foster, certainly has uncanny echoes of Martin Bashir's exposé of Michael Jackson's private life.

Just as Bashir bashed the pop star with his charm and smarm, so Lynn Alleway, allegedly a "friend" of Ms Caplin, somehow duped the golden couple into letting her camera follow their every move at the height of the "Cheriegate" saga.

The parallels are striking. While Jackson revealed his dodgy habit of sharing his bedroom with boys, Ms Caplin revealed her dodgy habit of sharing her bed with a man wanted on three continents.

Unlike Jacko, however, we get to actually see the pouting princess of Downing Street under the duvet with her partner. Sadly for anyone tuning in for a fly-on-the-ball documentary, the pair's only bedtime activity was reading the papers.

That Mrs Blair's closest chum would allow anyone to film her day and night at the height of the media frenzy only underlines her poor judgement in the affair.

But although, unlike the Bashir show, the documentary does not produce stunning revelations, it does allow another glimpse of the age-old story of what happens when a credulous gal falls for a charming cad.

Ms Caplin, who famously makes her money from giving clients such advice as "no-wheat-no dairy-no alcohol" and telling them to hug their inner crystal, is no dumb babe.

But as she stretches out like a cat on the carpet, presumably doing her energy-giving exercises, she clearly didn't recognise Mr Foster as the tabloid vermin others would run a mile from. Part Nigella Bites (see Carole flick her lovely tresses as she cooks), part The Osbournes (see Foster push his luck with coarse gags), part Friends (everything happened in their flat), this is trash TV reliant on vignettes and vagaries of human behaviour as opposed to an earnest study of the affairs of state. Only the pictures of the Blairs on the wall, intimate pics of Tony and Leo included, reveal that they had high-powered links.

At one rather bizarre point, Mr Foster despairs so much of his media image he even says: "Yes, OK, I'm conman Foster, I'm a fucking paedophile, I eat bats' heads." There are lovely snapshots of the conman's sleazeball side. We see the able-bodied Foster using a disabled person's pass in his car. We see him hiding – under his shirt – a T-shirt featuring the Blair family as he prepares to make his television statement about Cheriegate.

Most appalling of all, we see him – after a row with Carole – back at his sad batchelor pad playing a different tune to remind him of a different previous girlfriend. An Elton John song conjures up "Annette", another says "Belinda", yet another says "Darlene" (a former Miss World, he claims).

But as time goes on, it is clear that the penny has dropped for Ms Caplin and she says she was once happy with her relationship but "that's not the case any more". Their final hug before he flees to Ireland is followed by a resigned sigh from her.

Downing Street may be Neverland as far as Gordon Brown is concerned but its attractions must also be waning for Cherie's pal. It was, however, rather satisfying to see the conman himself finally conned into appearing in a film that allowed the general viewing public to see his true nature.