My brother is in a partnership. They have employed a person as a sub contractor (who is not registered as self employed or as a sub contractor). He no longer works for them and now wants to sign on. The Social Welfare office want a letter from him stating when he last worked. My brother knows that he has not paid any tax on any money he has earned. How will this affect my brother's business? I am presuming that someone will have to pay the tax that is owed.