National Insurance Number
1 November 2021
Must be 9 characters.
The first 2 characters must be alpha.
The next 6 characters must be numeric.
The final character can be A, B, C, D or space.
The first character must not be D,F,I,Q,U or V
The second character must not be D, F, I, O, Q, U or V.
The first 2 characters must not be combinations of GB, NK, TN or
ZZ (the term combinations covers both GB and BG etc.)