Outgoing UK prime minister Boris Johnson addressed the House of Commons for the last time overnight. Beset by self-inflicted scandals, Johnson is stepping down from the top role, forcing the ruling Conservative Party to choose a new leader who will be announced on 5 September. Conservative MPs have whittled the field for his replacement from eight candidates down to two. Rishi Sunak, the former Chancellor, and Liz Truss, the Foreign Secretary, will go head-to-head in a vote among all Conservative Party members. The winner will inherit a parliamentary majority and will become the next Prime Minister. BBC's political correspondent Rob Watson spoke to Susie Ferguson.