Section 3 of the Vexatious Litigants Act 1981
3. (1) If the Supreme Court or a Judge thereof is satisfied that a person has frequently and without reasonable ground instituted vexatious legal proceedings or procured vexatious subpoena, summonses to a witness, warrants or process to be issued or that any other person acting in concert with such a person has without reasonable ground instituted vexatious legal proceedings or procured vexatious subpoena, summonses to a witness, warrants or process to be issued, the Supreme Court or such Judge may after hearing such person and, if the case require it, such other person, or giving him, her or them an opportunity of being heard, by its, his or her order, declare such person and such other person to be a vexatious litigant.