A British man whose family contacted police after suspecting he was involved in Madeleine McCann’s disappearance was never fully investigated, the Standard can reveal today.

The expat, who was living in the Algarve at the time the child vanished, was put forward as a suspect by his brother but detectives failed to rule him out of the inquiry.

Today, on the fifth anniversary of Madeleine’s disappearance, the lawyer for her parents Kate and Gerry said she hoped the “crucial lead” will be investigated by Scotland Yard, which has launched a review of the case.

The man, who is named in police files but cannot be identified for legal reasons, was allegedly desperate to have a child but he and his then partner were unable to conceive.

His brother informed British officers the suspect told him and other members of his family that if he could not have a child he would kidnap one. The information was apparently passed on to the Portuguese authorities but the McCanns’ lawyer Isabel Duarte said he was never “properly investigated” nor eliminated from the inquiry.

The suspect — who lived in Espiche near Praia da Luz, where Madeleine vanished on May 3, 2007 — also had a boat in the marina at nearby Lagos.

Ms Duarte said the lead was all the more significant because of reports of a girl “remarkably like Madeleine” being dragged along a road leading to Lagos marina at 6am on May 4.

It was also revealed today that during efforts to track down a “significant number” of sex offenders, attempts to contact several of them were not successful and never followed up.

Ms Duarte added that police have never interviewed 28 employees of the Ocean Club, from where Madeleine disappeared at the age of three.

Church services to mark the anniversary of Madeleine’s disappearance will be held tonight in Praia da Luz and in the McCanns’ home town of Rothley, Leicestershire.