After a few days in the fortress suburbs of Johannesburg, a visitor could be forgiven for thinking that South Africa was well into the abyss. The City of Gold has always had a turbulent air; now it seems at its most jittery in years. As the security walls rise around homes and offices, so the sentries - and horror stories - multiply.

Over tea on Saturday, one of the more successful of the new breed of black business people shrugged as he explained how he had just spent R1.5m (£106,000) to move to a more secure home.