Long before Lord Bamford, the chairman of the machinery manufacturer JCB, invited Boris Johnson to speak at his company earlier this month, the billionaire had bulldozed his way into British politics. Johnson was paid £10,000 by the company three days before he gave his 18 January Brexit-themed speech, which was widely seen as his latest tilt at the Conservative leadership and which he peppered with repeated praise for the company’s business acumen and innovation. The payment was disclosed on the…