London—As if to underline the magnitude of the political earthquake that struck Britain this morning, Jeremy Corbyn, the newly elected leader of the Labour Party, said that his first official act would be to attend a “Refugees Welcome Here” rally today in London. A 100-to-1 outsider when he entered the race at the beginning of the summer, the veteran left-wing MP and chair of the Stop the War coalition had trouble scraping together the 35 nominations from his fellow Labour members of parliament. Branded a fringe figure by the media and party insiders, Corbyn’s forthright opposition to austerity—he was the only one of the four leadership candidates to vote against the Conservative