Science Fantasy, which also appeared under the titles Impulse and SF Impulse, was a British fantasy and science fiction magazine, launched in 1950 by Nova Publications as a companion to Nova's New Worlds. Walter Gillings was editor for the first two issues, and was then replaced by John Carnell, the editor of New Worlds, as a cost-saving measure. Carnell edited both magazines until Nova went out of business in early 1964. The titles were acquired by Roberts & Vinter, who hired Kyril Bonfiglioli to edit Science Fantasy; Bonfiglioli changed the title to Impulse in early 1966, but the new title led to confusion with the distributors and sales fell, though the magazine remained profitable. The title was changed again to SF Impulse for the last few issues. Science Fantasy ceased publication the following year, when Roberts & Vinter came under financial pressure after their printer went bankrupt.

New Worlds was a British science fiction magazine that began in 1936 as a fanzine called Novae Terrae. John Carnell, who became Novae Terrae's editor in 1939, renamed it New Worlds that year. He was instrumental in turning it into a professional publication in 1946 and was the first editor of the new incarnation. It became the leading UK science fiction magazine; the period to 1960 has been described by science fiction historian Mike Ashley as the magazine's "Golden Age".