Sadiq Khan was heckled and sworn at by a small group of protesters during an appearance at the Royal Festival Hall on Wednesday evening. Between four and six men and at least one woman, who appeared to be protesting about the Ulez expansion, shouted and interrupted the mayor during a ticketed event to promote his book, Breathe. They were sat in the middle of the 2,600-capacity hall, about 30 yards from the mayor on stage. The audience tried to drown out the shouts and called for the protesters to leave as they encouraged the mayor to continue reading extracts from his book. At one stage, one of Mr Khan’s brothers, who was sat with his wife near the protesters, stood up and told them to be quiet. One man approached him, threatening a fight.