Advisor to Prime Minister for Interior Affairs Rehman Malik Sunday left for London where he will head a Pakistani delegation at the meeting of Pak-British working group for anti-terrorism and human trafficking. During his two-day visit he will also meet MQM Chief Altaf Hussain besides high British officials. He will brief the British officials about the steps being taken by Pakistan for taking legal action against the accused in Mumbai attacks as well as the efforts being made to lessen Indo-Pak tensions.