When the Attorney General determines, after such investigation as shall be necessary, that any agency of state government charged with the implementation of any act of the Legislature is failing or refusing to implement such act, he shall notify the agency head by letter of such determination. If, within ten working days of the receipt of such letter, it is not established to his satisfaction that steps to implement the act are being expeditiously taken, and there is no valid reason for failing to do so, such as a failure of an appropriation, the Attorney General shall file an action in the appropriate court to compel implementation. In any such action the department head or the agency head shall defend the action. The costs and a reasonable attorney’s fee as fixed by the court shall be paid out of the appropriation to the department.