Martin has been Chief Executive of the Parole Board since 2015; and has overseen a 60% reduction in the number of outstanding parole cases; the recruitment of nearly two hundred new members; implemented a new strategy to improve progression of IPP prisoners; and a complete overhaul of digital working to introduce paperless working and digital recording of hearings. During 2020, Martin has driven performance at the Parole Board during the COVID-19 pandemic, using innovation to save thousands of hearings in jeopardy. He has also led the Parole Board through the Tailored Review and the upcoming Root & Branch review.

Prior to 2015 Martin had spent over twenty years in a range of senior operational and policy roles in the justice system, including: the HMCTS response to the public disorder in 2011; and as head of sentencing policy implementing LASPO 2012