Chicago cop Jim Brannigan (John Wayne) is on the trail of big time gangster Ben Larkin (John Vernon), when he is told by his superiors that he must take the next flight to London, because Larkin is in hiding there and Britain has agreed to extradite him. What Brannigan doesn't know is that Larkin wants him out of the picture and has hired a hitman (Daniel Pilon) to have him killed, and when Brannigan arrives in London and meets Jenny Thatcher (Judy Geeson), the policewoman who will show him around, the hitman arrives soon after. And there are more complications to come...
Written by Michael Butler, William P. McGivern, Christopher Trumbo and William W. Norton, Brannigan was more proof that John Wayne wished he had taken the Dirty Harry role, after the previous year's McQ. Here he is a tough Chicago cop who plays by his own rules, and this is made more evident by the transportation of his act to London, where the resultant culture clash is emphasised to comic effect. The head of the Larkin investigation in Britain is Sir Charles Swann (Richard Attenborough - I suppose Inspector Charles Swann didn't sound English enough?) and they, of course, do things differently on their side of the Atlantic, including letting Larkin move about as he pleases, keeping him under observation all the while.
Larkin is accompanied by his dodgy lawyer Fields (Mel Ferrer), who has set up an escape route via Ireland to South America, where Larkin can do all the larkin' about he wants. Unexpectedly, while enjoying a soapy massage at an exclusive health club where John Vernon fans get that nude scene they always wanted from him, the American gangster is kidnapped by British gangsters, who demand a ransom for his safe return. Brannigan is not impressed, either about having to wear a tie in British establishments or the limeys' mishandling of the case, and is more keen than anyone to see Larkin returned.
The script makes an attempt to go for the complex twists, which is mirrored in the various overcomplicated set ups that Brannigan has to deal with. Dropping off the money in a pillar box (at Piccadilly Circus!) leads to a chase around town and the coppers being fooled again, and the hitman devises a couple of Heath Robinson contraptions to see Brannigan dead, including the novel "bomb in the toilet" trap. Local colour is what it's all about, though, and it's curious to see Wayne in a post office or ordering a pint in a pub, where he starts a comedy brawl as if he was still in one of his Westerns. Would Clint Eastwood have done the same in the role, we wonder? Some regarded this as a rip-off, not of Dirty Harry, but of Eastwood's earlier Coogan's Bluff.
The supporting cast is also notable for its British celebs, not only the blustering Attenborough (who absurdly calls The Duke "You big sod!") or the demure Geeson, but actors of the calibre of Tony Robinson, of Baldrick fame, who gets pushed into the Thames by the Duke. The mega-star also beats up Brian Glover of "Tetley make Teabags - make Tea" fame, worries Anthony Booth of Till Death Us Do Part fame, and gets into a car chase with a Jaguar Mark 2 while driving a Ford Capri of, er, The Sweeney or The Professionals fame, which all adds to the fun. Although obviously past his prime, Wayne gets by on natural charisma, and the entertainment value of seeing him in 1970s London gives the film a unique selling point for British viewers, but the whole production resembles a plug for the tourist industry instead of the gritty action thriller it poses as, and the star was plainly long in the tooth for this sort of affair. Music by Dominic Frontiere.