Trainee solicitor Isobella Perrie Sullivan has been granted bail after she was caught driving a car bomb towards Northern Ireland in a suspected New IRA operation. Irish police said they made an 'extremely significant seizure' of a device on Wednesday afternoon made from military-grade plastic, which could have caused significant damage. Sullivan, 25, and a man in his 40s were arrested in the major investigation, with Irish news outlets reporting that the man was a suspected member of the New IRA's Dublin branch. The bomb was the most sophisticated that police had seized since the Troubles, sources told The Irish Times, pointing to the persistent threat posed by dissident republicans on both sides of the border. In an intelligence-led swoop, the Garda's Special Detective Unit stopped the vehicle in transit near the Irish border on Wednesday afternoon on the N2 south of Carrickmacross, County Monaghan. Gardaí then requested the assistance of the Irish Defence Forces EOD (Explosive Ordnance Disposal) team, which completed an examination of the vehicle. It is understood the device found contained suspected military grade explosives. Garda sources have described the bomb as 'highly sophisticated' and 'advanced'. The vehicle's female driver was arrested at the scene and remained in Garda custody today. Garda Commissioner Justin Kelly speaks to reporters today in Templemore, Co Tipperary