The Secretary of State for the Home Department (the Home Secretary) is the chief United Kingdom government minister responsible for law and order in the United Kingdom; his or her remit includes policing, the criminal justice system, the prison service, internal security, and matters of citizenship and immigration. The Home Office has also previously dealt with social issues, including social exclusion, equality and race relations, but the responsibility for these areas is now held by the Office of the Deputy Prime Minister.

Unlike many other governments, the British government has separate departments for the issues dealt with by the Home Office and for legal, judicial and civil rights issues; these have been dealt with by the Lord Chancellor's Department. The office of Lord Chancellor has frequently been attacked because his role (which spans all three branches of government) is frequently seen as obsolete and unsuited to a modern democratic form of government. There have been repeated calls for the scrapping of the office and its replacement with a Justice Department headed by an elected Cabinet member, or the merger of the department with the Home Office. In June 2003 the government announced, as part of a cabinet reshuffle, that it intended to abolish the Lord Chancellor and replace his department with a Department of Constitutional Affairs headed by a Secretary of State.

Because the Home Office was initially the primary government department with responsibility for domestic affairs, all subsequent domestic departments have effectively been created by taking responsibilities from the Home Office, leaving in addition to law and order a variety of miscellaneous tasks that have no yet been allocated to a government minister. Consquently the Home Secretary can find themselves dealing with as matters as diverse as wild birds in Scotland, which towns in England and Wales are entitled to call themselves cities or taking part in formal ceremonies such as the annointment of bishops in the Church of England. However it is the law and order function of the department that predominates overwhelmingly.

Home Secretaries since 1782