The band — according to Time magazine — had been playing Oh, Johnny, Oh Johnny, How You Can Love! When the sirens started to wail, and the bombs fell harder, Ken 'Snakehips' Johnson conducted more furiously and the band played louder.
One customer from the time remembered of the venue, "Although the Blitz was happening outside, you felt quite safe because you were underground, away from where the bombs were landing."
But two bombs had managed to find their way into an air shaft, and directly onto the dance floor of the Café de Paris.
Johnson — born Born Kenrick Reginald Hijmans Johnson — earned his nickname from the moves he learned under the great choreographer Buddy Bradley.
Though he could cut a pretty shape on the dance floor, it was as a bandleader that Johnson really made his name. His Rhythm Swingers — later renamed The West Indian Orchestra — were rock stars of their day, broadcast regularly on BBC radio.
In 1941, Johnson — just 26 years old — had secured a residency with his band at the Café de Paris, just off Leicester Square.
One bomb, says a report from the Liverpool Echo, "[tore] through the roof, exploded with a terrific report on a balcony immediately above the orchestra. Debris was hurled in all directions... the dancers, hurled to the floor by the blast, were lying everywhere — some dead, many more injured, and the more fortunate only dazed."
What had been a nightclub became a nightmare: "heaps of wreckage crushing the heaps of dead and maimed, a shambles of silver slippers, broken magnums, torn sheet music, dented saxophones, smashed discs."
Johnson, and most of his band, were among the 34-odd people killed. The young bandleader was later cremated at Golders Green Crematorium. For fans, it was indeed the day the music died.
One of the special constables first on the scene, A Nickel in the Machine tells us, was one Ballard Berkeley. In later decades, he would play the Colonel in Fawlty Towers.
The incident brought out the best and the worst in people; reports say that while nurses out for a night on the town immediately attended to casualties, other revellers began looting valuables from the injured and dead. They were chased off by air wardens.
A story like this wouldn't be complete without a Blitz spirit moment; that came, apparently, when one man, being stretchered out, piped up "At least I didn't have to pay for dinner!"
Stills taken from this YouTube video.