South Sudan’s parliament on Tuesday named as official leader of the opposition a member of the breakaway Sudan People’s Liberation Movement-Democratic Change, an offshoot from the ruling SPLM party.

Onyoti Adigo Nyikwec was nominated as leader of the largest opposition party in the legislative assembly of the semi-autonomous south, which is preparing for a referendum due in January that many in the south believe will see Africa’s largest nation split in two.

“It is the first time in the history of southern Sudan to have the leader of the opposition in the parliament,” said Nyikwec in his acceptance speech, one of four SPLM-DC parliamentarians in the 170-seat house.

“This is the real democracy which has been guiding the principles we fought for so many years,” he said.

SPLM-DC party leader Lam Akol, a former foreign minister, was the only challenger to south Sudanese President Salva Kiir in April’s elections.

Akol defected during Sudan’s 22-year civil war between the southern rebels and the government in Khartoum, and formed the SPLM-DC last year.

His breakaway group has been accused of working to undermine the upcoming referendum, and many ruling party members had rejected the SPLM-DC as a legitimate party.

Following their election in April, the four SPLM-DC members had their parliamentary immunity temporarily suspended during investigations into alleged connections to militia groups and the murder of a tribal elder — charges that were later dropped.

The new opposition leader said he backed independence, and called on southerners to work together to ensure the referendum happens smoothly.

“The referendum needs us to unite all our ranks together, so that we go to the referendum united as the people of southern Sudan for the independence of southern Sudan,” Nyikwec said, to loud applause from the parliament.

The referendum is a key provision of the 2005 peace deal that ended the south’s 22-year civil war with the north, during which about two million people were killed in a conflict fuelled by religion, ethnicity, ideology and natural resources, including oil.