The Government Legal Department (previously called the Treasury Solicitor's Department until 2015) is the largest in-house legal organisation in the United Kingdom's Government Legal Service. The Department is headed by the Treasury Solicitor. This office goes back several centuries. The office was enshrined in law by the Treasury Solicitor Act 1876, which established the Treasury Solicitor as a corporation sole (an office with perpetual succession). Employees of the department exercise legal powers which are vested in the corporation sole.