Prime Minister Shahid Khaqan Abbasi on Friday left for London on a two-day visit to address a conference in London School of Economics, official sources said. The sources said that the Prime Minister would address a conference at the London School of Economic. However, Foreign Office Spokesperson Dr Mohammad Faisal said that he was not aware of the Prime Minister's visit. "I will check and get back to you," Dr Faisal told Business Recorder, but he did not reply till filing of this report.