A landmark UK Supreme Court ruling has quietly redrawn the boundary of what it means to lead a company with integrity. In the matter of Spring Media Investments, the Court held that a director who delays a shareholder-agreed sale — believing, sincerely, that he is serving the company's best interests — may still breach his fiduciary duty under section 172 of the Companies Act 2006. The judgment establishes that good faith is not a private conviction but a public standard: directors are measured not by what they believed, but by how they actually behaved.