London Mayor Sadiq Khan, a frequent target of President Trump’s angry Twitter rants, mocked the American president as a “six-foot-three child in the White House” at an event in Westminster on Saturday, The Guardian reports. Speaking to a room full of teachers at an education event, Khan reportedly quipped that he’d been sure to turn his phone off but said: “For those of you that have your phones on, if somebody starts tweeting about me – a 6ft 3 child in the White House – can you let me know?” The jab triggered cheers and applause from the audience, according to The Guardian. The mayor’s comments come a couple weeks after Trump took to Twitter to dub him a “stone cold loser” ahead of his state visit to the U.K. Trump has also described Khan as a “national disgrace” and a “disaster” amid their long-running feud, while Khan has hit back and dissed the American leader as a “poster boy for racists.”