Kate and Gerry McCann travelled to Portugal for the libel trial of a Portuguese policeman who published a book including claims Madeleine McCann was dead only for the case to be put off today.

The couple had flown to Lisbon for the opening of Goncalo Amaral's libel trial in the capital.

But the judge ordered a postponement after Amaral's lawyer failed to turn up for health reasons, according to a court clerk.

The McCanns, of Rothley, Leicestershire, told reporters outside court they were not disappointed by the delay because a hard-fought injunction on further sale or publication of the book remained in place.

"Freedom of speech should not include distortion of the truth, lies, fabrication and slander," Mrs McCann said.

Mr McCann added: "The key thing here is we're here to fight for our daughter, and if anyone steps over the lines then they should be prepared to defend what they say in court."

He said the book had "damaged" the search for Madeleine because it encouraged people to believe she was dead.

"If people read it and believe she is dead then they will not keep looking for her and may not come forward with information they may have," he said.

Mr Amaral defended his right to give his opinion, telling waiting press as he left the court: "There is freedom of expression in Portugal."

Madeleine was nearly four when she went missing from her family's holiday apartment in Praia da Luz on May 3, 2007 while her parents dined with friends nearby.

Despite a massive police investigation and publicity worldwide, she has not been found.

Mr Amaral was involved in the initial investigation but was later taken off the case.

In his first book, The Truth Of The Lie, he claimed Madeleine was dead and questioned the McCanns' account that she was taken while they were eating with friends.

In September, after a year-long legal campaign, a Portuguese judge granted an injunction banning its further sale or publication.

It also banned Mr Amaral from repeating his claims about Madeleine or her parents.

The couple have previously said any money awarded in damages by the courts would be ploughed straight back in to paying for private investigators to probe their daughter's disappearance.

The scheduled start of the trial coincided with the launch of Mr Amaral's second book, A Mordaca Inglesa (The English Gag), at Lisbon bookshop Ler Devagar at 6.30pm, according to the shop's website.

The trial was adjourned to 12 January.