BBC News By Mark Simpson image copyrightMirrorpix/Getty Images image captionKing George V and Queen Mary arrive for the opening of the parliament of Northern Ireland in June 1921 Historians advising the government on how to mark the centenary of Northern Ireland have requested access to secret official files from the early 1920s. The request includes documents relating to the so-called B Specials, an auxiliary police force known officially as the Ulster Special Constabulary. Northern Ireland was created in 1921 after Ireland was partitioned. An eight-strong panel of academics was set up last year to advise the government on centenary matters. The Centenary Historical Advisory Panel is chaired by Queen's University historian Professor Paul Bew and includes academics from Cambridge University, Sheffield University and Ulster University.