A retired lawyer who has repeatedly accused Kate and Gerry McCann of covering up their daughter Madeleine's death is facing jail for harassment.

Tony Bennett has waged a campaign since 2007 against the Kate and Gerry McCann Photo: PAUL GROVER

Kate and Gerry McCann arriving at the Leverson Inquiry Photo: Eddie Mulholland

For almost five years, Kate and Gerry McCann have suffered the anguish of not knowing what happened to their daughter Madeleine.

Through it all, they have also had to contend with a sustained campaign of harassment conducted by a small band of fanatics convinced they had a hand in their daughter's disappearance.

Now, one of their main tormentors is facing jail for refusing to leave the McCanns' alone.

Tony Bennett has waged a campaign since 2007 against the couple – repeatedly accusing them of covering up the girl's death in leaflets, books and on internet postings.

On one occasion, the Madeleine Foundation, which he runs, handed out 1,500 pamphlets in Rothley, the couple's home village in Leicestershire, entitled "10 key reasons which suggest she was not abducted."

Another booklet has been posted by registered delivery to the McCanns' home.

Next month, a court will decide whether to jail Mr Bennett, 64, for contempt of court.

The action is being brought by Mr and Mrs McCann who have grown increasingly disturbed by Mr Bennett's attacks on them.

Mr Bennett is accused of flouting an agreement in the High Court – made in November 2009 – that he would stop repeating allegations that the McCanns were in some way involved in their daughter's abduction.

Since then, Mr Bennett, a grandfather-of-two from Harlow in Essex, who is obsessed with the case, has posted on the subject of Madeleine McCann's disappearance an astonishing 3,800 times on one website alone.

Lawyers acting for the McCanns accuse him of breaching the undertaking on at least 149 occasions. The list of alleged breaches is not exhaustive.

The McCanns' spokesman Clarence Mitchell said: "This has gone on for a long time and Kate and Gerry now feel enough is enough. It is obviously very distressing for them. The fact they are taking legal action speaks for itself.

"Tony Bennett is his own worst enemy by persistently doing what he does, he has brought this action on himself."

The couple, both doctors, live in hope their daughter may still be alive and continue the search for her.

A Metropolitan police review of the evidence, put together by Portuguese detectives, continues but is not thought to have produced any significant new leads in the search for Madeleine.

A draft order seen by The Sunday Telegraph, which a judge is expected to rule upon at a hearing in February, includes an option for Mr Bennett to be "committed to HM Prison for a period" to be determined.

Mr Bennett could also be fined and ordered to pay costs that are likely to bankrupt him.

The undertaking Mr Bennett signed – he will now claim he only agreed it under duress – prevents him from making a number of claims in relation to Madeleine's disappearance from her parents' holiday apartment in the Portuguese resort of Praia da Luz on May 3rd 2007.

At the time she was just three-year-old.

The agreement signed in court states: "The defendant [Mr Bennett] undertakes not to repeat allegations that the claimants are guilty of, or are to be suspected of, causing the death of their daughter Madeleine McCann; and/ or of disposing of her body and/ or of lying about what happened and/ or of seeking to cover up what they had done."

The undertaking also included the destruction of a book "What really happened to Madeleine McCann? 60 key reasons which suggest that she was not abducted" and a leaflet "What really happened to Madeleine McCann? 10 key reasons which suggest that she was not abducted."

But since that November 2009 undertaking, Mr Bennett has continued many of his activities.

The list of 149 alleged breaches, compiled by the McCanns' lawyers Carter Ruck, includes a book: "The Madeleine McCann Case Files: Volume 1" and a series of postings on the social networking website Twitter.

Mr Bennett runs the Madeleine Foundation, whose website has been subject to scrutiny by the McCanns' legal team, while also putting up 3,800 posts on another website The Complete Mystery of Madeleine McCann at a rate of about five a day.

Speaking to The Sunday Telegraph, Mr Bennett was largely unrepentant and seemingly happy to repeat some of the allegations that put him under threat of contempt.

He first became interested in the case while watching it unfold on television in 2007.

He attempted to bring a private prosecution against the couple in November 2007 for child neglect – on the grounds the couple were eating dinner with friends when Madeleine was abducted – but the case was thrown out in a magistrates' court.

Mr Bennett said: "I have done my best to comply with the undertaking but I would argue to the courts it was an unreasonably wide undertaking to sign.

"In the last two years I have not written specifically about the details of how she [Madeleine] might have died or how the body was hidden.

"It is my sincere conviction that one day I will be proved right. I truly believe that one day the truth will be told. And yes I am risking a breach of the order by saying that."

Asked how he felt about harassing a couple, grieving over the disappearance of their daughter, Mr Bennett replied: "The thing that came closest to harassment was when we distributed the '10 reasons' leaflet in Leicestershire in August 2009.

"Three of my colleagues in the Madeleine Foundation distributed a small quantity of leaflets in Rothley. I would honestly say that perhaps that was a leaflet distribution too far.

"If Madeleine was abducted I would accept what I have done is a wicked campaign of harassment. If I am wrong I am evil. But if I am right, I am a victim of simply having the desire to pursue the truth."