The UK Corporate Governance Code is not law, therefore compliance is not compulsory. The FRC asks companies to 'comply or explain' – either follow the Code or explain why they do not. The Code speaks a lot of sense on how a company should be directed.
Employing good corporate governance helps the company regulate risk and reduce the opportunity for corruption. Often, scandals and fraud within a company become more likely where directors and senior management do not have to comply with a formal governance code.