Britain's biggest investors are to put greater pressure on companies to sign up to the principles of corporate social responsibility, under tough new guidelines published yesterday by the Association of British Insurers. The move by the ABI, whose members control one quarter of the UK stock market, represents a significant shift by investors, who have traditionally seen social responsibility as a "distraction". Douglas Alexander, minister for corporate social responsibility, who addressed yesterday's ABI conference, signalled that the government might make a new operating and financial review - giving details on a company's approach to social and environmental issues - mandatory for the "most economically significant" companies...New research published by the ABI, shows that there are risks to shareholder value from human rights abuses, poor treatment of workers, suppliers and customers.