Hillary Clinton has begun a tour of Africa by delivering a blunt message to Kenya to worker harder to combat corruption.Clinton’s seven nation tour is designed to encourage trade with sub saharan African nations — but the US Secretary of State said concrete results would only come when the conditions were right. “Progress depends on good governance and adherence to the rule of law. That is critical to creating positive, predictable investment climates and inclusive economic growth” President Barack Obama sent a video message to the trade meeting, held in the country of his father’s birth. Under Washington’s African Growth and Opportunity Act, sub-saharan African nations can export some 6400 products duty free to the United States. But although the measure has existed for nine years, the 48 countries who qualify, make up just 3 per cent of imports into the USA and 1 per cent of America’s exports. Clinton’s mission is to seek ways of boosting that trade.