Thunder Rock is a 1942 British drama film directed by Roy Boulting and starring Michael Redgrave and Barbara Mullen, with James Mason and Lilli Palmer in supporting roles.

In despair at the way his countrymen seem totally oblivious to the ever-more impending doom which is about to engulf them, and appear to be content to go about their daily business as normal while all the time sleepwalking towards disaster, he decides to turn his back on Britain and find a far-flung location where he can withdraw from the world and all its contemporary woes.

He finally allows Melanie to read the tablet describing their deaths, and tells them all that the civilisation they knew is coming to an imminent end, and he has withdrawn to avoid being witness to its demise.

The film is based on the 1939 play Thunder Rock by Robert Ardrey, which had originally been a flop when staged in New York folding within three weeks,[1] but proved to be considerably more successful in London where it ran for months in the West End.

Critical opinion of the time in Britain was divided as to whether the additional material brought new depths to the story, or made too explicit things which Ardrey had preferred to leave to the audience's imagination and intelligence.

Several of the stage actors reprised their roles, including Michael Redgrave as Charleston, Frederick Valk as Dr. Kurtz, and Barbara Mullen (a later addition to the cast) as Miss Kirby.

[4] On its British release in 1942, Thunder Rock received mixed reviews, with critics eager to compare the screen version to the stage play, not always to the former's advantage.

"[5] The reviewer for The Manchester Guardian had also seen both, though not to the detriment of his regard for the film: "Robert Ardrey's Thunder Rock, still the best new play of the war, has been faithfully translated to the screen.

In his syndicated column, Walter Winchell called the film "a glowing fantasy that lights up the dark corners of many current issues...it manages to be high-class without being highbrow".

[8] Dorothy Kilgallen, writing in her Voice of Broadway column, urged any of her out-of-town readers planning a visit to New York to "drop in at the World Theatre...and see the film Thunder Rock...you'll remember it a long time, and it may not play your town.

As the writer disillusioned by the world's complacent response to fascism, Michael Redgrave gives one of his most complex and tormented performances, as he regains the crusading spirit from his encounters with the victims of a shipwreck that occurred years before on the rocks near the lighthouse he now tends.

With a bullish contribution from James Mason and truly touching support from ghostly emigrée Lilli Palmer, this is one of the Boulting Brothers' finest achievements.