A thorn in the side of relations between South Africa and Britain was removed yesterday when three opponents of the South African government left the British consulate in Durban.
On leaving, Paul David and Archie Gumede were promptly arrested and later charged with treason. William Nair was not arrested. Their 90-day ''sit-in'' in Durban was in protest against the practice of detention without trial in South Africa. But the incident also soured relations between South Africa and Britain.
Pretoria was angered that Britain did not evict the protesters. In retaliation, South Africa refused to return to Britain four South Africans who were to be tried for alleged arms smuggling.
The three remaining protesters decided to leave the consulate when Pretoria announced early this week that it was dropping all ''preventative detention'' orders, under which the government can imprison people it regards as threats to state security or law and order. The three were sought under this sort of order.
Mounting criticism in the US over such detentions and South Africa's racial policies seemed to play a role in prompting Pretoria to release some of the opponents it had detained.