What is the British equivalent of Social Security?
National Insurance number
From 1984 until 2011, when a person was allocated an NI number they also received a plastic 'numbercard' of similar proportions to a credit card with the number raised on the front. Prior to 1984, a manila notification card was issued instead.  The card is only used as a reminder of the number and the card itself is not needed to start work, and is not considered a valid identity card.  Numbercards were phased out from September 2010, and the issue of numbercards ceased completely in October 2011.  NI numbers are now notified by letter.[15]