If the deal goes ahead it will be South Africa's biggest weapons purchase since the end of apartheid. The four Upholder class boats are the most advanced conventionally powered submarines in the world but have been lying idle since they were scrapped after Britain moved to an all-nuclear submarine fleet.
The diesel-electric submarines were built by Vickers at Barrow-in-Furness at a cost of about pounds 1bn in the early 1990s but only saw brief service with the Royal Navy. The MoD had hoped to sell them to Canada but they have been laid up in Barrow awaiting sale. Christopher Bellamy