How does CSI (Comprehensive Sickness Insurance) relate to being lawfully resident? 

CSI stands for Comprehensive Sickness Insurance and it was a requirement for certain people to have it to be considered lawfully resident in the UK. 

EU citizens had been living in the UK under freedom of movement rules. These rules no longer apply to the UK because the UK decided to end freedom of movement as part of leaving the European Union.

To be able to live in another EU country, after an initial period of 3 months, EU citizens had to be a ‘qualified person’ under these freedom of movement rules to reside in the UK lawfully. The main categories were worker, self-employed, jobseeker, student or self-sufficient. 

The latter two categories (student and self-sufficient) had to be financially self-sufficient and also have this ‘CSI’ to exercise to be considered lawfully resident.

Note: this question, like other FAQs on Comprehensive Sickness Insurance (CSI), relates to applications for British citizenship, when considering whether periods of past residence were lawful.

CSI is not required to apply for pre-settled or settled status under the EU Settlement Scheme. Also, once pre-settled or settled status has been granted, you are lawfully resident, and you do not need CSI.