Madeleine McCann's mother is attending a Portuguese court for the start of the family's libel action against a former police chief which could see them receive £1m in damages if they succeed.
Kate McCann will be accompanied by her mother Susan Healy for the first hearing of the case against Goncalo Amaral, who published a book making allegations about the three-year-old's disappearance in 2007.
The McCanns have strongly denied the accusations and say the former detective's claims have damaged the hunt for Madeleine and exacerbated the anguish suffered by her relatives.Their lawyer Isabel Duarte is expected to set out the case - on behalf of Mrs McCann, her husband Gerry and their twins Sean and Amelie, now eight - at Lisbon's civil court.
The McCanns pose with a computer-generated image of their daughter
Mrs McCann, who is travelling to Portugal without her husband, could have been called as a witness, but is not expected to give evidence.
Instead, a number of relatives will appear in the witness box. They will speak about the "damage" caused by Mr Amaral's book which, they claim, poisoned public opinion in Portugal against the family and allegedly deterred people from hunting for Madeleine.
Spokesman Clarence Mitchell said: "Kate and Gerry McCann remain very confident that they will win the case.
"They have a strong case against Mr Amaral. The matter is now in the hands of their lawyer as it goes through court."
Goncalo Amaral's book "poisoned public opinion", it is claimed
It is understood Mr McCann is staying at the family home in Rothley, Leicestershire, to look after the couple's children.
Madeleine, who was nearly four at the time, disappeared from her family's holiday apartment in Praia da Luz in the Algarve on May 3, 2007, as her parents dined at a nearby tapas restaurant with friends.
British detectives launched a fresh investigation into her disappearance in July - two years into a review of the case - and believe she could still be alive.
The Portuguese investigation into Madeleine's disappearance is officially closed.
The libel case will be heard today and tomorrow. It will then be adjourned until next Thursday when the court will sit again for two days. A final hearing is expected on September 27. The judgement is expected to be deferred.
