More than 50 potential new leads into the disappearance of Madeleine McCann surfaced last night as details of a previously unknown police file were released.

Scores of sightings were reported after the Portuguese police formally closed their investigation in July 2008 but the majority were not followed up.

The 2,000 page dossier contains hundreds of witness statements, photographs and unsolved lines of inquiry.

The sightings ranged from Europe to the west coast of the US, Hong Kong and Australasia and were passed on by independent witnesses and international police forces.

Madeleine was three when she vanished from her family’s apartment in the Algarve resort town of Praia da Luz in May 2007.

Her parents Kate and Gerry, both 41, have fought to keep their daughter’s plight in the spotlight, hiring their own private investigators to continue the search.

They only discovered the existence of the Portuguese police file last month during their court battle against Goncalo Amaral, the disgraced detective who tried to publish a book accusing the couple of covering up their daughter’s death.

The extensive dossier was released by the Portuguese authorities in Portimao yesterday after a request by The Daily Telegraph and includes:

:: Information about a British-registered white Mercedes box van which travelled on a ferry from Tarifa to Tangiers to Morocco from Spain with false number plates in the week Madeleine went missing. Its driver could not be traced

:: CCTV footage of a young girl resembling Madeleine which was taken in a supermarket in New Zealand in December 2007.

:: Repeated sightings of a girl who looked like Madeleine in Gent, Kortrijk and Bruges in Belgium in November 2008.

:: Information about a girl similar to Madeleine wearing a pyjama top similar to the one she was wearing when she disappeared who was with an “unkempt” couple in Agua Marina, near Murcia in Spain on May 15, 2007.

:: Reports in October 2008 of a girl matching Madeleine’s description being dragged along a road towards Faro airport on May 3, 2007 – the night she disappeared.

:: An account from lorry driver Michel Guidard who saw how a young girl who looked like Madeleine wearing a dirty yellow jumper and naked from the waist down being held at gunpoint at a motorway toll on the A20 near Paris in August 2008.

:: Photographs from the internet uncovered by a female French detective showing images of sexual abuse which involved a girl resembling Madeleine.

The previously unseen CCTV footage from New Zealand was sent to the Portuguese police by Interpol in Wellington in July 2008, just as they closed their investigation.

A female security guard at a supermarket in Dunedin, on the south island, thought she saw Madeleine on December 6, 2007.

She said the girl and the man holding her hand had British accents. Attempts to identify them failed and the information was passed to the Portuguese.

A hand-written note on the papers in the file said: “This has been checked by PJ and has no relevance to this investigation.”

The McCanns, from Rothley in Leicestershire, are furious that they were not told about the leads at the time and that they were not followed up to their satisfaction.

After successfully blocking the publication of Mr Amaral’s book The Truth of the Lie last month, Mrs McCann said: “There are instances where information which we think is very credible and worthy of information has not been actioned.

“We’re gutted, it’s absolutely shocking and difficult. Some of the information handed in was very credible, it’s heartbreaking to know that it seems to end there.”

Mr McCann was angered by Inspector Ricardo Paiva, their former liaison officer, who was responsible for collating any information that came into the police about Madeleine after the formal Portuguese investigation came to an end.

He said: “Inspector Paiva believes Madeleine is dead. How can he investigate thoroughly if he believes that?

“We know now there is a lot of information just filed away – and that is not acceptable.

“Once the file has been closed, what has actually been done? Next to nothing.”

Isabel Duarte, the couple’s solicitor, asked to see the police file after Inspector Paiva mentioned it during the court case.

“It is a disgrace that none of this information was given to Kate and Gerry. Some of the photos are shockingly similar to Madeleine.

“Every piece was treated the same way – Ricardo Paiva writes on it ‘this is not relevant to the investigation’.

“I said to him ‘How can you find a person when you are not looking for them?’”