I searched the public register of Data Controllers to see which Electoral Registration Officers were
registered for London Boroughs. Using various combinations of search terms including searches by place names I found that for 27 London Boroughs the Electoral Registration Officer had registered
(separately) as a Data Controller. I could not find any evidence that the Electoral Registration Officers for Bexley, Hackney, Haringey, Hounslow, Lambeth, Southwark were registered as Data
Controllers. Perhaps the ICO shed some light on this.

Request: Electoral Registration Officers