National Insurance Number

[Allied]

How is your NI number made up? Who decides what letters and numbers to use? I have looked on the government sites but nothing tells you. My two sons got their NI cards 5 years apart and their numbers are almost identical. Is it to do with where you live?

Does anyone know?

[dzug]

http://en.wikipedia.org/wiki/National_insurance

and

http://www.hmrc.gov.uk/ebu/ni2003.pdf

have quite a bit of info

Your sons would have been allocated their numbers at the same time, despite the gap between their getting cards