The prime suspect in Madeleine McCann’s disappearance is just days away from being released from prison after denying a British police request for an interview over the three-year-old’s disappearance.

Christian Brueckner, 49, is due for release from prison for an unrelated rape conviction in the same area where the British toddler went missing from her family’s Portugal holiday flat close to two decades ago.

A former criminal associate of the German national has claimed Brueckner confessed to the toddler’s abduction in 2008, a year after her disappearance.

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Helge Busching claims Brueckner made the confession during a conversation about the case.

“I tell him like this, I don’t understand how somebody can rob the little children from a hotel. And then he said to me, ‘yeah, she was not screaming’,” Busching said.

Christian Bruckner is a suspect in the disappearance of British toddler Madeleine McCann. Credit: AAP

McCann disappeared while on holiday with her family in southern Portugal in 2007. Credit: AAP

Busching says he told British police about the alleged confession, but it wasn’t until 2017 that it caught the attention of detectives.

“Brueckner was such a good circumstantial suspect. His previous convictions for similar offences, we know that he had broken into holiday homes before,” investigators noted.

Brueckner remains a key figure in Scotland Yard’s ongoing Operation Grange inquiry into Madeleine’s disappearance.

However, a last-ditch effort to interview the German national was rejected, leaving investigators with no access to their prime suspect.

“Now I know there will come out a really dangerous man,” Busching warned.

Brueckner denies any involvement in Madeleine McCann’s disappearance and is soon to be a free man.