Does my employer have the right to distribute a notice stating that I was the worst performing engineer for the month to everyone in the department I work in. As I am not entirely responsible for achieving an outcome to each job I felt very humiliated by his actions.
There is no specific law as such, but this is pretty poor practice. Suggest you raise it by asking for a meeting with your manager. If you are still not satisfied wth the outcome, raise it as a formal grievance (which the employer has to investigate).
Performance issues should be discussed between manager and employee - not published on noticeboards.
If your employer put out a notice only stating you were the worst performer, then I agree that you should complain, but if the notice lists all engineers in performance order, and you just happen to be at the bottom of the list, then I think this is perfectly legitimate and you have no reason to feel victimised.