A first design of the 300 GeV project was put to the CERN Council in 1964 but this project meant building a second laboratory and thus required a new location.

In 1969 J. B. Adams was appointed Director of 300 GeV project.

In 1971 CERN Council approved the construction of a second laboratory, adjoining the existing site, with a Super Proton Synchrotron accelerator (SPS) initially planned for an energy of 300 GeV.  J. B. Adams was appointed as Director-General of Laboratory II, which was administratively separate from the Laboratory I. At the beginning of 1971 CERN Laboratory II consisted of only 4 staff. Soon a small personnel section was set up, in collaboration with Laboratory I, to handle personnel matters including staff recruitment. Laboratory II contained executive groups dedicated to building the SPS.

In 1976 the two CERN laboratories were united. Laboratory II was renamed SPS Division and still directed by J. B. Adams.

On 17 June 1976, the SPS machine accelerated protons to 300 GeV for the first time (improvements in performance allowed it to reach a peak energy of 500 GeV at the end of 1978).

In 1977 the experimental research programme started.