Conventional cold war spy thriller which overcomes its familiarity thanks to a wonderful ensemble of British character actors, and John Huston's expertise in the genre. It's quite uneven, but still absorbing entertainment. Paul Newman is an agent for MI6, who goes undercover as an Australian diamond thief in order to expose a gang trafficking imprisoned Communist agents to the East.
This casting is undeniably offbeat, but Newman is at least nonchalantly charismatic. He is backed up by Dominique Sanda as his implausibly elegant intermediary. And there is the superlative support of many veterans of the cold war on screen, including Harry Andrews and Michael Horden. Best of all is James Mason as the contemptible villain, a Commie spy posing as a Tory MP.
Maurice Jarre's score derived from Russian folk music is a genre cliche, but still works. The twisty plot is interesting and there are striking, touristic locations in Malta, Ireland and central London. Admittedly, the premise is much better than the resolution, but there is that satisfying mood of pessimistic melancholy which is standard in cold war spy films.
Credibility becomes dangerously stretched in the climax when Newman suddenly demonstrates a talent for swimming underwater, in his suit. There's nothing new here, but it's a lot of fun for fans of the genre. And a cameo by Nigel Patrick is bonus. By the way, the undercover spy doesn't wear a Mackintosh, that is the name of his Whitehall contact.