Madeleine has been missing since May 3British and Portuguese police are discussing plans to re-interview the friends who dined with Madeleine McCann's parents on the day she disappeared.
Meetings have taken place in the Algarve about how fresh interviews would be carried out.
Leicestershire Detective Superintendent Stuart Prior returned from discussions with counterparts in Portugal today.
Madeleine went missing from her family's holiday apartment in Praia da Luz on May 3 last year while Gerry and Kate McCann ate dinner at a nearby tapas bar with friends.
Detectives have focused on the witness accounts given by the group, the so-called "Tapas Nine", to try to establish a timeline of events on that evening.
Mr Prior flew to Portugal to discuss mutual legal assistance - the process where evidence is gathered in one country to help an investigation in another.
A Leicestershire police spokeswoman said: "Since Madeleine's disappearance, we, together with other law enforcement agencies, have been working closely with the Portuguese authorities.
"Mr Prior has attended a series of meetings with his Portuguese counterparts. He travelled to Portugal on Tuesday and returned this morning.
"He went to discuss how the request for mutual legal assistance is to be executed and to seek clarification over elements of the request."
The process itself could involve Portuguese police writing questions to be put to the friends on their behalf by their British counterparts.
Officers involved in the investigation in the Algarve could still fly to Britain to sit in on the interviews, which are likely to be held at a location in Leicestershire.
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Tapas Nine: Fiona Payne, Jane Tanner, Russell O' Brien and Rachael Oldfield are likely to be re-interviewedThe McCanns' spokesman Clarence Mitchell said: "The sooner this re-interviewing takes place the better.
"The friends are very keen to help police understand their original statements. No one will be changing their story.
"We are not aware that Kate and Gerry are to be re-interviewed at this stage, but if so, that's not an issue."
The McCanns, from Rothley in Leicestershire, were joined at the tapas restaurant on May 3 by Jane Tanner, Dianne Webster, Matthew and Rachael Oldfield, Russell O'Brien and David and Fiona Payne.
A Home Office spokeswoman said: "We have already confirmed that we have received a mutual legal assistance request from the Portuguese authorities in connection with the investigation into the disappearance of Madeleine McCann.
"We are currently awaiting clarification from the Portuguese authorities over elements of the request.
"Home Office officials continue to work closely with the police to assist the Portuguese authorities with this investigation."
Read more: http://www.dailymail.co.uk/news/article-527864/British-Portuguese-Madeleine-police-meet-discuss-interviewing-Tapas-Nine.html#ixzz13pV1uItH