During a talk at a Danish high school, movie director Nikolaj Arcel said that he ask Søren Pilmark not to talk or be nice to Anders W. Bertelsen during production, because it would improve the acting (the two characters are supposed to dislike each other, the one being superior to the other). This resulted in Anders W. Bertelsen being somewhat nervous and cautious around Søren Pilmark. When shooting was done Arcel told Anders W. Bertelsen all about the secret and the two actors became friends.
The character of the villain, played by Søren Pilmark, is according to directer Nikolaj Arcel based on Danish prime minister Anders Fogh Rasmussen.
The novel on which this is based, Niels Krause-Kjær's "Kongekabale", was written shortly after the writer quit his job as spin-doctor for the Conservative party in Denmark. During his employment at the party it went through a power struggle between two different wings of the party. It is generally thought that this power struggle is the inspiration for the novel.
At minute mark 27:55 as Ulrik Torp joins Peter Schou and a group of journalists, the author of the novel on which the film is based, Niels Krause-Kjær, can be seen on the right. He's wearing glasses and is dressed in a dark pullover and light trousers.
The interior shots of Christiansborg (The parliament) are not shot at Christiansborg, but at Copenhagen city hall.