The controversy over Cherie Blair's relationship with conman Peter Foster is set to be reignited with the airing of a BBC fly-on-the-wall documentary.

The film follows the Australian and his partner Carole Caplin during the latter stages of the Cheriegate storm in December.

She saw the film for herself and I think she agreed that the film is honest and accurate Alex Holmes

In the film Ms Caplin - Mrs Blair's personal trainer - claims that Foster was treated like a "terrorist" by UK immigration and it was the "mysterious powers that be" that ensured he was deported from Ireland back to Australia.

He had helped the prime minister's wife to buy two flats in Bristol.

Speaking ahead of Thursday's airing of the documentary Miss Caplin said the people behind Foster's deportation "were acting to protect whatever they thought they needed to protect, but they've gone way over the top.

"The officers at Dublin airport said British officials had requested Peter not be allowed into Ireland because of a supposed risk that he might try to slip into Britain illegally."

Honest and accurate

In an interview with the Mail on Sunday, Miss Caplin criticised the documentary maker, Lynn Alleway, for betraying her by showing Foster in a negative light.

He is shown in the programme saying that Mrs Blair knew about his criminal past and that she lied when she said publicly she had not known about his record.

The documentary was defended by its executive producer, Alex Holmes, who said he did not think it was "reasonable" for Miss Caplin to feel betrayed.

"She saw the film for herself and I think she agreed that the film is honest and accurate and that is the undertaking we gave to her in the first place," he told BBC Radio 4's Today programme.

The Conman, His Lover and the Prime Minister's Wife will be shown on BBC One on Thursday at 2100.