Focus Features

Bill Naghy (right) plays the owner of the radio ship.

Today, British rock stars are knighted. In the mid-1960s, they were rebels, and so were the people who tried to play their music on the radio.

The DJs responded by broadcasting rock from ocean-going ships anchored safely beyond the reach of the government.

One such ship and its band of madcap platter-spinners is the subject of "Pirate Radio," an entertaining and high-spirited, if ultimately insubstantial, movie directed by Richard Curtis. Though inspired by historical fact, this particular story presumably is fictional.

The soundtrack, however, is wonderfully real. Provided by an array of the bygone era's musical stars ranging from the Rolling Stones to Leonard Cohen with everything in between, it's the beating heart of the movie.

Philip Seymour Hoffman stars as the only Yank among the DJs. Kenneth Branagh plays Alistair Dormandy, the priggish government official who makes it his mission to get the musical "sewer" off the air by any lawful means that can be invented.

"Pirate Radio" devotes itself mostly to its eccentric shipboard characters. They include a lesbian cook (Katherine Parkinson), the ship's natty owner (Bill Nighy) and his innocent but eagerly corruptible godson (Tom Sturridge) in addition to the radio people and occasional visiting groupies.

Storywise, aside from a couple of more or less expendable subplots about professional rivalry and misbegotten romance, the movie is as fluffy as an ABBA tune. There's nothing about civil rights and only one oblique mention of Vietnam. Instead, it's all about the stuffy government's obsession with shutting down the pirates despite their huge popularity with the public.

Sir Alistair eventually succeeds in crafting the necessary legislation. But Mother Nature gets to the renegade ship before the police, setting up a funny and wildly improbable final scene that will warm the hearts of rock lovers everywhere.

You don't need a plot to enjoy "Pirate Radio," however. The music will do just fine. If the soundtrack is available on CD or online, you'll want to get it. Especially if you're lucky enough to have come of age during those golden formative years of rock 'n' roll.