LONDON — About 1,400 children were sexually exploited in a northern England town, a report concluded Tuesday in a damning account of “collective failures” by authorities to prevent victims as young as 11 from being beaten, raped and trafficked over a 16-year period.

Report author Alexis Jay cited appalling acts of violence between 1997 and 2013 in Rotherham, a town of some 250,000. The independent report came after a series of convictions of sexual predators in the region and ground-breaking reports in the Times of London.

“There were examples of children who had been doused in petrol and threatened with being set alight, threatened with guns, made to witness brutally violent rapes and threatened they would be next if they told anyone,” Jay said. “Girls as young as 11 were raped by large numbers of male perpetrators.”