Excerpt from the Official UK visa application website in South Africa:
IMPORTANT CHANGES FOR SOUTH AFRICAN VISITORS TO THE UK
Following Britain's first global review of who needs a visa to come to the UK, a visa regime has been introduced in South Africa.
Since 3 March 2009, South African nationals have been required to have a visa to enter or transit the UK. A temporary exemption is in place for any South African passport holder who has previously travelled to the UK and has evidence of their visit in their current passport, for example a UK entry stamp. This temporary exemption ends on the 1 July 2009 and from that date all South African passport holders will require a visa to enter or transit the UK.
From 1 July 2009 all Swaziland and Lesotho passport holders will also require a visa to travel to the UK.
The visa you choose depends on your reason for visiting the UK and how long you plan to stay.
