The Court may, on the application of the defendant, or of the Government pleader, of which seven days, clear notice in writing has been given to the plaintiff, order that the permission granted to the plaintiff to sue as an indigent person be withdrawn—

(a) if he is guilty of vexatious or improper conduct in the course of the suit;

(b) if it appears that his means are such that he ought not to continue to sue as ¹[an indigent person]; or

(c) if he has entered into any agreement with reference to the subject-matter of the suit under which any other person has obtained an interest in such subject-matter.