Dr D AKA Subvertiser is a British street artist based in London. He began helping an old school friend to fly post in central London in the early 1990s. He began creating his own art by cutting sections from billboards and moving them on to others to make new words and phrases. From this, he developed his poster art, making the posters himself and putting them up on walls, billboards and bus stops. Other 2D and 3D projects followed.

His fake street signs, containing warnings for the passing public, included ‘Curfew – Social Cleansing’, which was displayed at the London Design Museum’s ‘Hope to Nope’ show in 2018. Dr D's visual activism also focuses on personalised street art pavement messaging under the name ‘Worship The Ground’.

His poster series 'H.M.P. Manchester Open Prison', including the poster 'Do As We Say, Not As We Do', first appeared in Manchester's Northern Quarter on 5 November 2020. The series of 6 posters was based on an earlier 'H.M.P. London' series. The Manchester series focused on the impact of the coronavirus lockdown in Manchester and the battle between Greater Manchester Metropolitan Mayor Andy Burnham and the Prime Minister, Boris Johnson.