Students and/or self-sufficient persons, can meet the requirement of Comprehensive Sickness Insurance if the applicant provides an EHIC card from their own country

An EHIC card from the UK is not valid for this purpose.

The applicant needs to show that they have held such a card throughout the period of residence as a student and/or self-sufficient person. This may require a letter from the authority in their own country issuing the card, to confirm the validity of the card and the date it was issued.

The card itself is not mandatory as long as the EHIC coverage was continuous and a letter to confirm such continuous coverage is provided, a letter from the authority of the issuing EU country stating that you were insured and eligible for EHIC during the relevant period would suffice.

If you submit an EHIC which does not cover the whole of the period relied upon, or does not feature a valid from date, you must also submit evidence from the issuing authority confirming that you held a valid EHIC card for the period relied upon.

Form E121/S1 is the equivalent of EHIC for pensioners.

See: Evidence of Comprehensive Sickness Insurance (CSI) - UKCEN Citizenship and Residence for European Nationals and their families .