The wall of silence maintained by police during their search for Madeleine McCann is in accordance with strict Portuguese laws, lawyers said yesterday.  

Criticism of police has centred on their refusal to reveal any details of the investigation, to make public appeals or even to update the McCanns on the progress of the inquiry. 

However, under the law in Portugal such information is confidential. Anyone official who releases it could face criminal procedures. 

The restrictions are set out in Article 86 of the Penal Process Code of Law, which states that the "process" of a police investigation must not be disclosed. 

Artur Rego, a lawyer in Praia da Luz, where Madeleine was snatched, said the strictly limited supply of information emerging from the police was "perfectly normal". 

However he did add that there were two exceptions to the law, which could apply in this case. The top investigator can decide to authorise the release of corrections to information in the public domain which is wrong. 

He can also intervene to release appeals in cases with "special public repercussions" - where public safety is at risk.

Police have refused to reveal if they have considered these exceptions. In a reverse of the British law, information is made public when someone is charged, or a case is dropped.