Madeline McCann has been missing for 11 days and Portugal police admit they have no leads. Here we look at the various theories surrounding her disappearance

Paedophile gang

Officers fear she may have been snatched by an organised gang who had the resources to watch the apartment for a number of days. They would also have arranged transport and possibly a house where they could hold her. This could link to the three adults spotted on CCTV at a Portuguese petrol station.

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Lone paedophile

A major line of inquiry. There have been sightings of a girl of Madeleine's age with a mystery man in the area. A man was also spotted on a nearby beach taking photos of young children, including Madeleine.

Jealous mother

A grieving mother, possibly mentally ill, could easily have blended in at the resort and taken the girl when she knew her parents were not there. But the only e-fit is of a male, so many discount this theory.

Drowning

There have been suggestions Madeleine left the flat by herself and went looking for her mother. Officers checked early in the investigation if she had wandered the 500 yards to the beach. Dogs followed a scent to a supermarket en route to the sea but the trail went cold. Increasingly unlikely theory as time passes.

Opportunist paedophile

Believed to be another major line of inquiry. A paedophile could have chanced upon the opportunity to snatch her. Roy Whiting was a classic opportunist, grabbing Sarah Payne off a country lane during the day.

Childless couple

Madeleine may have been kidnapped to order for a couple hoping to pass Madeleine off as their own. They will almost certainly change her appearance, maybe cutting her hair or dyeing it. Police have stressed that Madeleine's distinctive right eye, where her pupil runs into her iris, will make this more difficult.