• Goncalo Amaral accused Madeleine's parents of faking her abduction

• He was ordered to pay €500,000 in damages after losing his libel battle

• But today Amaral posted copy of judgement overturning original decision

• McCanns lawyer 'disappointed' and vows to appeal to the Supreme Court

Portuguese detective Goncalo Amaral has won his appeal against his court libel defeat to Madeleine McCann's parents.

The former police chief had previously been ordered to pay Kate and Gerry McCann €500,000 in damages in April last year after accusing them of faking their daughter's abduction.

The appeal decision now paves the way for Mr Amaral's book ‘The Truth of the Lie’ to be sold again in the shops in what would be a devastating setback for the McCanns.

Editor Guerra e Paz are expected to rush out new copies so they can hit the shelves next week, netting Amaral a potential fortune. 

Today Mr Amaral posted a copy of the 16-page judgement overturning the original decision on an Internet blog.

The last page of the document, signed by three appeal judges and dated April 19, confirmed the original ruling was being revoked.

Amaral lost his long-running libel battle over his controversial 2008 book claiming the McCanns had faked missing daughter Madeleine's abduction after she died in their Algarve holiday apartment.

He was also ordered to pay interest after a Lisbon judge ruled he had overstepped freedom of speech limits in The Truth Of The Lie.

After the verdict, the McCanns announced they would plough 'every penny' of the payout into the hunt for their daughter, who was three years old when she vanished on May 3, 2007.

But Amaral's appeal, which he confirmed the following month, thwarted their hopes of spending the money.

The McCanns's Portuguese lawyer, Isabel Duarte, confirmed she had learned of the appeal decision this afternoon, adding that she was 'disappointed' but not surprised.

She said Madeleine's parents had instructed her to launch an appeal of their own which will be decided by Portugal's Supreme Court.

She said: 'I have just learnt that the three appeal court judges have decided to overturn the original decision in favour of my clients.

'It was a unanimous decision. The original decision has been revoked.

'I and the McCanns are obviously disappointed but I am not surprised because one of the judges ruled in favour of a previous appeal overturning a ban on the book.

'This decision was an appreciation of the law and not the facts.

'We can appeal to the Supreme Court which we will do as we have instructions from our clients.'

She added: 'My understanding from reading the appeal ruling is that the judges have decided Amaral was entitled to write a book the court calls a literary book.

'The court is basically saying he had the right to express his opinions. We obviously hope the appeal will succeed.

'The McCanns never received any compensation money after the original decision although the money was deposited at the court so there is no money to return to Gonzalo Amaral.'

Clarence Mitchell, spokesman for the McCanns, was unavailable this afternoon.

Amaral could also not be immediately contacted.

The appeal verdict comes a day after the detective in charge of the search for Madeleine said police still believe she could be found alive.

Madeleine disappeared in Portugal nearly nine years ago, just days before her fourth birthday, and officers have continued to hunt for her ever since. 

The head of Scotland Yard's homicide squad, Detective Chief Superintendent Mick Duthie, insisted there is 'always a possibility' she will be discovered safe as he justified the ongoing operation.

Earlier this month, Home Secretary Theresa May granted the Metropolitan Police £95,000 so they could continue the search for Madeleine, codenamed Operation Grange, for six more months.

DCS Mick Duthie said that it could be extended into next year if police need to continue following up leads.

'There is always a possibility that we will find Madeleine and we hope that we will find her alive,' he told the Evening Standard.

'That's what we want and that's what the family and the public want and that is why the Home Office continue to fund it.'