The first UK specialists parachuted in to help Portuguese police find Madeleine McCann have left their jobs.

Det Supt Graham Hill and psychologist Dr Joe Sullivan helped the investigators narrow down a list of potential suspects and offered interview techniques.

They arrived in Praia da Luz within 48 hours of Madeleine's disappearance nearly four years ago, but diplomatic sensitivities delayed confirmation of their presence for several days.

They and colleagues later advised Leicestershire police who pursued British leads in the hunt for Madeleine.

The two men led the Behavioural Analysis Unit at the Child Exploitation and Online Protection Centre and are the latest in a small exodus of its staff.

CEOP insists the the unit is being retained and even expanded to improve the range of expertise it offers police forces around the world.

The unit has been at the forefront of dissuading certain interrogators from the 'Life on Mars' style of questioning.

Det Supt Hill is returning to Surrey Police, from where he was on a long secondment and Dr. Sullivan has not had his consultant contract renewed.

CEOP says both men will be missed and replaced and denies it is scaling down its child-centered operations as it prepares to be absorbed into the new National Crime Agency.