Where a party has been declared a vexatious litigant and institutes proceedings without obtaining the required leave of court, and persists in advancing the same arguments that have been repeatedly dismissed across multiple courts, a court is entitled, in exercising its discretion under Rule 47(3), to order such party to furnish security for costs in order to protect the opposing party, the integrity of court processes, and the administration of justice. The failure of a party to disclose their financial position when resisting a security for costs application weighs against them.