The ISU is a British trade union representing some of the operational staff in the Borders, Customs and Immigration functions of the Home Office.
It was a split from the Society of Civil and Public Servants (SCPS),[8] founded in protest at the SCPS calling for the repeal of the Immigration Act 1971.
[9] The ISU is politically independent and not a member of the Trades Union Congress.
PCS, the SCPS's successor, sees ISU as a yellow union, as some senior managers encouraged its splitting off, although its independence has been certified by the Certification Officer.
[16] In 2012, ISU members followed other public sector unions in agreeing to strike against changes to civil service pensions.