The prime suspect in the high-profile case of Madeleine McCann’s disappearance has declined to be interviewed by the Metropolitan Police, the force has said.

The Met said an international letter of request was sent to Christian Brückner, ahead of his imminent release for a separate offence, which he later rejected.

German national Brückner, 48, has never been charged with any crime in relation to the McCann case and denies any involvement.

Madeleine vanished in the Portuguese resort of Praia da Luz in 2007. She and her siblings had been left sleeping in a holiday apartment while her parents, Kate and Gerry, went for dinner at a nearby restaurant.

They had checked in on the children periodically until Kate discovered Madeleine was missing at around 22:00.

Brückner is currently serving a seven-year prison sentence in Germany for the rape of a 72-year-old woman at her home in Praia da Luz in 2005.

German authorities have said he will be released by Wednesday.

Det Ch Insp Mark Cranwell said Brückner remains a suspect in the Met Police’s own investigation into Madeleine’s disappearance. He has been the prime suspect in the German and Portuguese investigations since 2020 and 2022, respectively.

“We have requested an interview with this German suspect but, for legal reasons, this can only be done via an International Letter of Request which has been submitted,” Det Ch Insp Cranwell said.

“It was subsequently refused by the suspect. In the absence of an interview, we will nevertheless continue to pursue any viable lines of inquiry.

“We can provide no further information while the investigation is ongoing.”

Madeleine’s disappearance has become one of the highest-profile unsolved missing person cases in the world.

German prosecutors have pointed to evidence – including mobile phone data – indicating Brückner may have been in the area when she vanished, and have consistently insisted that they think he is responsible.

However, they have not found strong enough evidence to bring charges.

Brückner, who spent many years in the Algarve, was a drifter, a petty criminal and a convicted sex offender. He has several previous convictions, including for sexually abusing children in 1994 and 2016.

Portuguese and German police conducted a fresh search between where the McCanns had been staying and addresses linked to Brückner in June this year, but this yielded no breakthroughs.