High Quality Content by WIKIPEDIA articles! The Home Office is the United Kingdom government department responsible for immigration control, security, and order. As such it is responsible for the police, UK Border Agency, and the Security Service (MI5). It is also in charge of government policy on security-related issues such as drugs, counter-terrorism, and ID cards. It was formerly responsible for the Prison Service and Probation Service, but these are now under a newly created Ministry of Justice.