UK Immigration Service

The United Kingdom Immigration Service, (previously known from 1920 to 1933 as the Aliens Branch and from 1933 to 1973 as the Immigration Branch), was the operational arm of the Home Office, Immigration and Nationality Directorate. The UK Immigration Service was, until its disbandment in 2007, responsible for the day-to-day operation of front line UK Border Controls at 57 ports "designated" under the Immigration Act 1971 including airports, seaports, the UK land-border with Ireland and the Channel Tunnel juxtaposed controls. Its in-country enforcement arm was responsible for the detection and removal of immigration offenders such as illegal entrants, illegal workers and overstayers as well as prosecutions for associated offences. On its disbandment, Immigration Service staff were re-deployed within the short lived Border and Immigration Agency which was replaced by the UK Border Agency which, in turn, was replaced by UK Visas and Immigration.

The enabling Act which provided the basis of immigration control was the Aliens Act 1905 and it was followed by the Aliens Restriction Acts of 1914 and 1919. The powers exercised by Immigration Service officers were/are largely based on the Immigration Act 1971 that came into force on 1 January 1973 and its associated rules. Other subsequent legislation includes:

For the earlier part of its history the Immigration Service's work was dominated by control of passengers at seaports and the control of crews. By the 1920s, The Immigration Service was divided into districts under the charge of an Inspector. The Immigration Officers’ grade was confined to men aged over 25. Those under 25 were automatically classified as Assistant Immigration Officers. Immigration Officers enjoyed an annual salary of between £200-300 and controlled passengers and seamen at ports throughout the United Kingdom. This included Ireland until the creation of the Irish Free State in 1922 and, even after this, UK immigration officers controlled Irish ports until 1925 while the new administration made its own arrangements.

By the late 1950s the numbers of arriving passengers at airports overtook that of seaports for the first time and the distribution of staff began to reflect this. Immigration control at airports gradually changed from the late 1990s onward as a new emphasis was given to controlling passengers in visa issuing posts abroad. During the 2000s new technologies opened up opportunities to create a new "flexible" border control that better focussed its resources on high risk passengers.

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Wikipedia