The EM-2, also known as Rifle No.9 Mk1 or Janson rifle, was an experimental British assault rifle. It was briefly adopted by British forces in 1951, but the decision was overturned very shortly thereafter by Winston Churchill's incoming government in an effort to secure NATO standardisation of small arms and ammunition. An innovative weapon with the compact bullpup layout and an optical sight, it used one of the early intermediate cartridges (a concept introduced by the Germans with the 7.92×33mm Kurz) as a result of combat experience and German advances in weapons design during World War II.