The current House of Commons has 126 women among a total of 646 MPs – 19.5 per cent of the total.
In 1997, when Tony Blair was photographed amid a sea of female Labour MPs, whose number had suddenly shot up to 102, it seemed that the UK was also going to take a world lead, but that promise has not been fulfilled.
Despite the dire prophecies of economic catastrophe, the law has come into force without driving out any major company.
"The most alarmist people told us the economy would suffer, that investors would flee Oslo, that the level of competence on the boards would plunge," Marit Hoel, the head of Norway's Centre for Corporate Diversity said.
This is partly because of the voting system, but it also reflects British political culture.
A coalition of feminists and public sector trade unions first introduced positive discrimination to British politics, aided and abetted by the slightly old-fashioned Labour leader, John Smith, when they decreed that half of the new candidates in winnable Labour seats would be chosen from all-women shortlists.