The couple are suing a former Portuguese detective over claims he made in his book, which they say exacerbated their anguish.

Kate and Gerry McCann are said to be disappointed at the decision

A request by Madeleine McCann's parents to give evidence at a Portuguese libel trial over a book by a former local police chief has been rejected, according to a family source.

 Kate and Gerry McCann are suing Goncalo Amaral over claims he made in The Truth of the Lie, which they say damaged the hunt for their missing daughter and greatly added to their anguish.

 The McCanns are also taking legal action against his publisher and the makers of a documentary based on the book.

 They had wanted to testify in the court case, which is taking place in Lisbon.

Goncalo Amaral at the launch of his book in 2008

But a family source said permission had been refused ahead of the next hearing date, which is on Tuesday.

 The couple are said to be disappointed by the decision, and their lawyer Isabel Duarte is likely to appeal against the judge's decision.

 An application by Mr Amaral to give evidence is also understood to have been turned down.

 Mr McCann's sister Trish Cameron told the court last October that the family's pain over Madeleine's disappearance was "multiplied 100 times" by the book, while the trial previously heard how Mrs McCann had considered suicide in the aftermath of its publication in 2008.

Madeleine McCann disappeared from her family's holiday apartment in 2007

Madeleine's mother travelled to Lisbon at the start of the trial, and her husband has attended several times in the hope of being able to give evidence.

 

Madeleine, who was then nearly four, 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 restaurant with friends.

 

 British detectives launched a fresh investigation into the youngster's disappearance in July this year - two years into a review of the case - and made renewed appeals on television in the UK, the Netherlands and in Germany.

 

After shelving their inquiry into Madeleine's disappearance in 2008, Portuguese authorities said in October that a review had uncovered enough new information to justify reopening it.