In a word mischief. He still imagines that he can somehow wind up leader of the Tory party and Prime Minister. Had he kept out of May’s cabinet he might very well have done so. But he took on the job of Foreign Secretary and blew whatever reputation he had, depending on your perspective of the great political showman.
He has been a disaster at the foreign office. Most of the time he is clueless and talks in slogans. Several times he has dissolved under forensic questioning by tough political commentators. He is distrusted in Washington, Paris and Berlin. The Americans consider him a clown and a liar, the French ignore him and the behind the scenes German opinion of him is best left unsaid here. British influence on the world stage has perhaps never been lower; only in Libya, which has several governments, did he make an impact with one.
So to boost his credentials he has once again pedalled the proven falsehood that leaving the EU will free up £350 million per week to go straight into the NHS. Either he is even worse than we thought at paying attention to detail and reading briefing papers, or he knows very well this is untrue. Some angry Tories have demanded May sack him. She does not need to. He is self-destructing.