Johannesburg - The expulsion of the National Union of Metal Workers of South Africa (Numsa) from the ruling African National Congress (ANC) is set to re-draw the country’s political landscape.

Beneath an avalanche of acronyms, arcane trade union processes and parochial infighting, something big is stirring in South African politics.

For decades the 350 000-member union has been a pillar of support for the ANC.

During the anti-apartheid struggle the union provided key logistical support, and since the advent of democracy in 1994 has served as one of the main suppliers of the ANC's political shock troops.

Numsa provided bodies at rallies, funding for party coffers and brain power.

But no more. During May's election Numsa refused to back the ANC, criticising the party as corrupt and against the poor and calling on President Jacob Zuma to step down.

The ANC still won, but with its lowest ever share of the vote.

This past Saturday the ANC-allied trade union umbrella group Cosatu sealed the divorce by expelling Numsa from its ranks.

READ: Numsa expulsion: What it means for the ANC

"It is arguably the most important political development of South Africa's post-1994 era," according to Dale McKinley, an independent political researcher.

First and foremost Numsa's departure symbolises a fracturing of an alliance that has returned five consecutive ANC governments.

The ANC, although by far the country's most powerful political actor, has chosen to rule in coalition with the South African Communist Party and Cosatu.

But the left wing of that coalition is increasingly uneasy.

Expelled ANC official, Julius Malema, has already set up a rival party, the radical Economic Freedom Fighters, which came third in the polls with 6% of the vote at the last election.

"The ANC over the course of a number of years has seen its intellectual base eroded," said political and labour analyst Daniel Silke.

Analysts see the expulsion as another step toward Numsa building an opposition party that could tap into popular anger and outflank the ANC on the left.

Spear of the workers

"This development can never be celebrated," said ANC's secretary general Gwede Mantashe, describing Numsa's departure as "disappointing and tragic".

READ: Mantashe: Numsa expulsion overall bad

But at the same time Mantashe rubbished Numsa's allegations as "unfounded".

While analysts do not believe that Numsa will metamorphose into a strong political party, any shedding of votes away from the ANC could hurt the party, particularly in local government.

The ANC "will have difficulty maintaining control”, according to Silke.

In a show of solidarity with Numsa, seven other unions decided on Monday they would also "suspend" their participation at Cosatu's executive meetings.

The group of seven said that Cosatu, once the envy of workers organisations around the world, "has been reduced to a factional shell of its former self and glory."

Numsa itself said Cosatu had "managed to achieve what the apartheid regime failed to do, which is to destroy a federation that has been both a shield and a spear in the hands of the workers".

Numsa's expulsion could also cause more labour turmoil as unions fight for turf and members.

"I fear we may well see further labour unrest in South Africa going forward," said Silke as unions widen their focus from traditional wage settlements negotiations.

"We will obviously see inter-union or intra-union rivalries," said Silke.

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