Jean-Pierre Bemba, the Congolese ex-vice president whose war crimes conviction was quashed on appeal last week, will seek his immediate release on Tuesday from the International Criminal Court (ICC).

Bemba, 55, has been in the ICC detention centre for a decade since his arrest in 2008. The Democratic Republic of Congo opposition leader was convicted in 2016 of crimes against humanity and sentenced to 18 years in prison.

But that conviction was overturned on appeal last Friday in a major setback for prosecutors. Appeals judges said they could not pin responsibility on Bemba for the killing and raping of civilians by soldiers under his command.

He was the highest ranking official among only four people who had successfully been prosecuted at the permanent war crimes court since it was set up in 2002, and the reversal of the judgment against him dealt a blow to the prosecutors.

Normally suspects are immediately released after an acquittal, but Bemba also faces a separate charge for witness tampering during the trial. His lawyers say the decade he has already spent in jail far outstrips the ICC’s maximum five-year-sentence for witness tampering.

Upon release, which could come as soon as Tuesday, Bemba is expected to leave the Netherlands for neighbouring Belgium where some members of his family live.

His freedom could shake up politics in the Democratic Republic of Congo where he is still popular and presidential elections will be held in December.

Despite being behind bars, Bemba came third in a recent opinion poll by the Congo Research Group.