- 3 updates
Scotland Yard's review of the investigation into Madeleine McCann's disappearance, called Operation Grange, was launched in May 2011.
Last month, Detective Chief Superintendent Hamish Campbell said the review has identified "both investigative and forensic opportunities" and "more than a handful of people of interest".
As they marked the sixth anniversary of Madeleine's disappearance last month, Kate and Gerry McCann said they were encouraged by Operation Grange and that the police seemed "more determined than ever".
The couple said their hopes of finding her were "reaffirmed" following the discovery of Amanda Berry, Gina DeJesus and Michelle Knight in Ohio a decade after they went missing.
Home Secretary Theresa May is set to announce a full-scale Scotland Yard investigation into Maddie's disappearance.
A full investigation would allow police to interview suspects in Britain, though they would seek the assistance of the Portuguese to carry out there inquiries there.
The Home Office said it "remains committed" to supporting the search for Madeleine McCann, who disappeared from her family's holiday apartment in Portugal's Praia da Luz over six years ago.
A Home Office spokesman said: "We have always said we would provide the Metropolitan Police with the resources they need to investigate her disappearance".
UK Government lawyers travelled to Portugal to discuss new leads in the case of missing Madeleine McCann with their Portuguese counterparts, it has been confirmed.
London's chief crown prosecutor Alison Saunders and her deputy Jenny Hopkins flew to Portugal with Scotland Yard detectives in connection with the police force's review of the case.
Madeleine was nearly four years old when disappeared from her family's holiday apartment in Praia da Luz in Portugal's Algarve on 3 May, 2007, as her parents Kate and Gerry dined at a nearby tapas restaurant with friends.
A Crown Prosecution Service (CPS) spokesman said: "Prosecutors from CPS London, and investigators from the MPS [Metropolitan Police Service], visited their Portuguese counterparts on April 17-18 to discuss possible next steps in relation to the disappearance of Madeleine McCann.
"We continue to work with the police on this case."