Hi There are quite a number of reasons for being on a nil tax code. The most common one is for sub postmasters who are paid a salary by the post office for example and run a convenience store in the same place, then they account for their whole income by doing a tax return. Are you worried about your empoyer finding out about your bankruptcy?
just that the payroll system at ny office, i think shows my tax code and didnt want people seeing it, in case they say something to someone, even though I know its personal info