Shellie has 20 years-experience working within the Probation Service in a range of operational roles. Since 2008 Shellie has specialised in working with Terrorism Act offenders and operated as a Probation Counter Terrorism Lead in both regional and national roles within the Joint Extremism Unit from 2015-2020. This included operational delivery, project design and implementation, as well as strategic and policy roles. Since 2020 Shellie has been a lead inspector with HM Inspectorate of Probation with subject lead responsibility for extremism. In 2021/22 Shellie led the thematic inspection of electronic monitoring, helping shape £183 million pounds investment in future services.