So listen very carefully.
Between 1920 and 1970 there was the Immigration Branch of the Home Office.
Between 1970 and 2007 it became the United Kingdom Immigration Service.
In 2007 it became the Border and Immigration Agency.
On All Fool’s Day, 2008, the Border and Immigration Agency was put into a shotgun three-way with UKVisas (which operated courtesy of the Foreign Office) and the Detection function of Her Majesty’s Revenue and Customs. This rag-bag became the UK Border Agency, in a pale imitation of the US Border Patrol — the main difference being that the USBP is the largest sworn, armed agency in the United States, while UKBA delegated enforcement to Capita at a cost of £30 million. And Crapita enforced by text messages.
Or as Antoine-Laurent de Lavoisier had it:
Dans la nature rien ne se crée, rien ne se perd, tout change.