Koussa, who has long been one of the most feared members of Muammar Gaddafi’s revolutionary committee, replaces Abdel Rahman Shalgam in the role.

Koussa held the post of secretary of the Libyan People's Bureau in London until 1980 when he was expelled after threatening that the Libyan revolutionary councils would execute Britons as payback for the UK granting asylum to dissidents.

Koussa was later a key player in the settlement with the US over the Lockerbie bombing and became Gaddafi’s main contact with Western intelligence agencies.

Shalgam will become Libya's new ambassador to the UN.

At its annual meeting, the congress also merged or scrapped several ministerial positions. The Information, Electricity, and Water & Gas ministries were all abolished.

Abdulhafez Zlitni, previously planning minister, will now head the joint planning and finance portfolio.

Former Finance Minister Mohamed al-Huwayj will take over the industries, trade and economy ministry. Baghdadi al-Mahmudi will retain the role of prime minister.

In March 2008, Gaddafi announced that he would scrap most of the country’s ministries, leaving only the defence, public security, foreign affairs, justice and finance ministries intact.