Directors of listed companies should adopt a new principle in the Combined Code which concerns upholding high ethical standards of integrity and probity. The recommendations come form the Institute of Chartered Accountants of Scotland, which proposes that ethics should be 'clearly reflected in all statements issued by companies'. As it stands now, the Combined Code on corporate governance for UK listed companies doesn't have a stated principle on ethical standards, but the chairman and non-executive directors are expected to uphold them. ICAS is now urging this to be the case for all directors. 'We are not claiming that an ethical principle will clean up all bad business practice but ensuring the directors - the individuals at the top of a business - must explain how they apply this principle could be an effective way of embedding ethical considerations throughout a company,' ICAS president Douglas Nisbet said. Questions on whether the Code's provisions on the independence and length of service of non-executives are fully appropriate following recent board performance issues have also been raised. ICAS suggests that NEDs may often need more experience and knowledge of the business in order to fulfil their role effectively. 'Long-term corporate strategy may benefit from longer serving directors who have experienced the business cycles in that industry,' it said.