The official title was changed from "Metropolitan Police" to "Metropolitan Police Service" as part of the "PLUS Programme" in 1989, under the then Commissioner Sir Peter Imbert, following the presentation of a report entitled "A Service for Change: Report on the Corporate Identity of the Metropolitan Police" to the service's Policy Committee by Wolff Olins corporate identity consultants in August 1988. The Metropolitan Police Marine Policing Unit assisted in the aftermath of the 1989 Marchioness disaster, whilst in 1990 the Service was faced with the Poll tax riots. There was a great deal of media coverage of the 1992 killing of Rachel Nickell, after which a police sting operation against innocent prime suspect Colin Stagg was criticised as entrapment. Robert Napper, who committed a double murder in 1993, was convicted of the manslaughter of Nickell in 2008.