the Home Office
noun

(1)  the UK government department that deals with matters inside the UK that are not the responsibility of other departments, for example justice and the rules for people from other countries entering the UK

(2) a room or area in someone's home that they use to work at their job

The Cambridge Dictionary

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In these troubled times, the international meaning of "home office" on most lips is definition (2) above. However, if you have to do with the U.K. note today's OWAD meaning: a ministerial department of Her Majesty's Government responsible for immigration, security and law and order.

The Home Office is responsible for policing in England and Wales, fire and rescue services in England, and visas and immigration, 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.

The Cabinet minister responsible for this department holds the title Home Secretary, and is currently Ms Priti Sushil Patel

The Home Office, which is considered to be one the Great Offices of State, continues to be known, especially in official papers and when referred to in Parliament, as the Home Department.

Source: Bryan Gibson - The New Home Office

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Practice OWAD in a conversation:

"Some Europeans hold the view that the UK's HOME OFFICE has issued too little information, too late."