Edison Lighthouse were a British pop act of the kind the early-1970s charts produced in number: more a studio project built around session musicians than a settled band. Their one great moment, "Love Grows (Where My Rosemary Goes)", released in 1970, was a sunny, brisk slice of bubblegum pop sung by Tony Burrows, and it shot to number one in the UK.
Burrows was famously the voice on several different one-hit acts at once, and Edison Lighthouse, as a touring entity, was assembled partly after the fact. The hit, in other words, came before the band fully existed, and nothing under the name ever matched it.
On streaming, "Love Grows" sits near 372 million plays, and the rest of their catalogue, including a re-recording of the same song, trails far behind, the next distinct track barely reaching three million. That sends the ratio above 26, far past our 5.0 line.
By our measure Edison Lighthouse are a certified one-hit wonder of the purest kind. Theirs is the classic studio-pop story of the era: one irresistibly cheerful single, built and sung by jobbing professionals, that became a chart-topper and remains, by an enormous margin, the only thing the name is remembered for.