Legendary cricket star Sir Ian Botham started a 160-kilometer long charity walk in Sri Lanka today from Killinochchi in the Northern Province.The eight day walk in the humid heat of the tropical island has been organized by the middle-aged former all-rounder to raise money for charity that works for the rural poor children in South Asia.Botham has raised more than 20 million dollars for charity with his walks since 1985, but it is for the first time that he has ventured outside Britain with his philanthropic work.