The USA for example has a law which requires an alien to carry [immigration documents / ID](https://www.uscis.gov/ilink/docView/SLB/HTML/SLB/0-0-0-1/0-0-0-29/0-0-0-8289.html) on their person at all times. When flouted it is a misdemeanor and punishable by up to 30 days imprisonment.

Does such a law for aliens exist for the UK and does my credit/debit card with my name suffice as ID (not for driving, just for example if a ticket officer wants to check my ID on the metro) in the UK?