This story originally appeared in Los Angeles Times. The BBC issued a formal apology after broadcasting a controversial performance from the rap-punk group Bob Vylan at England's Glastonbury festival.

The prime minister is involved; so is the U.S. deputy secretary of State. The BBC is changing policies. But Bob Vylan remains steadfast.

London punk-grime duo Bob Vylan are the subjects of a criminal investigation following their set at Glastonbury. This is the story behind the biggest talking point of this year's festival