A new requirement for registered terrorist offenders in Northern Ireland to provide seven days notice before any cross-border travel is a proportionate step towards meeting the continued threat level, the High Court heard today. Counsel for the PSNI and British Government argued that the obligation could act as a deterrence against crime. Three people subjected to the regime as Registered Terrorist Offenders (RTOs) are taking legal action over its introduction. They include Derry man Anthony Lancaster, 58, who received a suspended sentence for acting as master of ceremonies at a 32 County Sovereignty Movement. In 2015 he was convicted of assisting in arranging or managing a meeting be addressed by a person who belonged or professed to belong to a proscribed organisation.