On their 1980 triple album 'Sandinista!,' the Clash covered even more ground than they had on their groundbreaking 'London Calling' the year before. From deep funk and dub mannerisms to hard-edged rock and Motown-inspired pop, the record is a virtual smorgasbord of sounds and styles. Among all that, the band looked back on a forgotten group from pop music's past: the Equals.

Formed in 1965, the Equals stood apart from many of the other bands on the U.K. circuit. The multiracial group combined elements of pop, soul, rock and ska into its own distinct sound. With their 1968 single, 'Baby Come Back,' the band hit international success. The record reached the Top 40 in the U.S. and the No.1 spot in England.

Written by guitarist Eddy Grant, 'Police on My Back' originally showed up as the flip side of a single from 1968. It was also included on the U.S. version of the 'Baby Come Back' album. (In 1983, Grant would score a No. 2 hit in the U.S. with 'Electric Avenue.') The Equals would have a handful of modest hits in England, and even though 'Baby Come Back' was to be the biggest, 'Police on My Back' took on a life of its own after the Clash covered it.

The Clash turned the mid-paced soul-pop song into a charged-up, full-powered rocker. Like on the original version, the Clash's cover features guitars that sound like police sirens during the intro. But unlike the original, the Clash's sirens are blaring and loud.

All the pieces are there from the Equals' version, but the Clash make it all sound more desperate and defiant. And In the process, they make a great song even better. The urgency found on their version invites volume cranking. In many ways, 'Police on My Back' was just waiting for the Clash to come along.

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