Missing: Madeleine McCann was taken from the Ocean Club in Portugal

Detectives investigating the disappearance of Madeleine McCann have issued a new request for help to the Portuguese authorities.

The development came as a senior Scotland Yard officer said the “tempo” of the inquiry into the missing toddler was “moving forward.”

Deputy Assistant Commissioner Martin Hewitt, who is overseeing the operation, said the Yard had sent a third international letter of request to Portuguese officials linked to their inquiries.

He said: “Clearly the investigative tempo is moving forward as we are progressing the investigation and the work we are asking the Portuguese to undertake for us. We are carrying on our liaison at all levels.”

Members of the inquiry team, including Detective Chief Inspector Andy Redwood, were in Portugal again today on a “routine visit” to meet counterparts from Portugal’s Policia Judiciaria.

Madeleine was nearly four when she disappeared from her room in the Ocean Club complex in Praia da Luz where she was staying with her family in 2007.

Scotland Yard launched a fresh investigation into the girl 's disappearance last July – two years into a review of the case – and made renewed appeals on television in the UK, the Netherlands and Germany.

Detectives in the UK must submit International Letters of Request to their counterparts overseas in order to get action undertaken in a foreign country.

Recent discussions between the two forces are believed to have centred on a burglary gang who had targeted homes in the resort at the time Madeleine vanished.

Mobile phone records are said to have revealed that three suspected burglars repeatedly called each other in the hours after Madeleine disappeared.

Mr Hewitt said so far the Yard had not asked the Portugese authorities to interview or arrest any suspects.

Scotland Yard has played down speculation of imminent arrests in the case saying they are pursuing several lines of inquiry. Met officers have been to Portugal more than 20 times in the past 18 months.

In October, Portuguese authorities said a review had uncovered information prompting them to reopen their own inquiry.

No-one has been arrested.