Samples from resort town being tested

London: Crucial new DNA tests that could hold the key to the Madeleine McCann investigation are being carried out in Britain.

The tests are looking for traces of the toddler's DNA from material gathered around the resort town of Praia da Luz in Portugal, including alleged blood samples found in an apartment close to the one from where she disappeared on May 3.

Results of the tests taking place at the Forensic Science Service laboratory in Birmingham could be sent to Portugal within days. Reports on Tuesday cast doubt on DNA evidence found in the family hire car that caused Portuguese police to officially name Kate and Gerry McCann as suspects.

But British sources close to the investigation insisted yesterday that "very few people" know exactly what forensic material has been gathered and point out that many of those criticising the investigation are basing their arguments on false assumptions about the facts.

As an example, a claim by the McCanns' supporters that toxicology tests could not have been carried out on hair samples found in the couple's hire car because the root was missing is said to be factually incorrect.

Instead, those involved directly in the investigation are said to remain confident about the forensic material that has been gathered.

Sources stress that despite the failure of Portuguese police to seal off the McCanns' apartment or to secure the couple's hire car - in which vital evidence is believed to have been found - the British forensic scientists working on the case have taken the risks of contamination into account. They are also said to be fully aware of the similarities in the DNA of Madeleine and her siblings and to have taken these into account when submitting their findings to Portugal.

"The work that has gone on is very thorough and involves a very painstaking process of testing, checking and re-checking," said an official involved in the investigation. "These people are some of the world's leading forensic scientists and they do not reach their conclusions lightly or without being aware of the possible problems with the material they are testing."

Madeleine was six days short of her fourth birthday when she disappeared. The current forensic testing follows the submission of a first batch of results to Portugal two weeks ago by the British experts.