Millie Small singing with the Spencer Davis Group

With international sales of 5m copies in 1964, the year of its release, the hit single My Boy Lollipop, sung by Millie, who has died aged 72, “opened the door for Jamaican music to the world,” said the producer Chris Blackwell. 

So begins Chris Salewicz's Guardian obituary of Millie Small.

She may have been a one-hit wonder, but he argues that it was an important hit:

What was at first considered a novelty record helped shift the parameters by which British listeners understood music, adjusting their ears to the offbeat but addictive ska rhythm

You can hear Millie Small singing on this Spencer Davis Group track. The piano at the start, as he confirmed in the comments on another Liberal England post, was played by Peter Asher.