"People who have wanted to do something [about apartheid] have realized that the easiest something to do is to switch their bank accounts," says Mike Flynn, spokesman for Britain's Anti-Apartheid Movement.

The actual money involved wasn't terribly large. But it kept on growing. Oxfam withdrew its account from Barclays. So did Balliol College, Oxford. So did churches and municipal councils.

So, above all, did college and university students. Barclays share of total student accounts dropped from 25 per cent to 17 per cent. And students, while they may be poor today, tomorrow will be lawyers, doctors, and even bankers.

More damaging than the withdrawals was the publicity about them. The Anti-Apartheid Movement and the National Union of Students organized a major campaign around the slogan "Boycott Boerclaybank."

That hurt. It hurt even more, potentially, abroad. In the U.S., Barclays has $22 billion in assets and 7,500 employees and is set, so it has hoped for a major expansion.

In a rare bankerly bow to public opinion, Basil Hersov, chairman of Barclays South African subsidiary, told a press conference in Johannesburg that "the cost of being in South Africa, in terms of the obstructions and difficulties this generated for Barclays operation in other parts of the world, was no longer tenable...."

There are no certainties about the net benefits to the anti-apartheid cause of corporate disinvestment, any more than there are about sanctions themselves.

All that's certain is that people power is having an effect in the most direct of all possible ways: on the balance sheets of companies that until now have done well out of South Africa' resources, including black labour....

None of the victories will come easily. A British government spokesman has already said that Barclays decision will have no effect on its anti-sanctions policy. But Margaret Thatcher and the others may have at last encountered a force stronger than they: ordinary people who have discovered that they do matter after all – sometimes.