Following the retirement of Philip Noel-Baker as the Member of Parliament, Johnson retained Derby South at the 1970 general election for the Labour Party, and was an assistant government whip from 1974 to 1975.
Following Philip Noel-Baker's retirement as Member of Parliament, Johnson retained Derby South for the Labour Party in the 1970 general election and served as an assistant government whip from 1974 to 1975.