Culture: Do you feel sorry, punk. Well, do ya?

Pauline Kael, the late film critic of The New Yorker, must be spinning in her grave. In her 1971 review of Dirty Harry (pictured), she described Clint Eastwood as a walking advertisement for fascism. As far as she was concerned, the 6ft4in actor was a right-wing Neanderthal who tapped into the most primitive instincts of movie audiences. She never would have dreamt that in August of 2008 he would become the subject of a retrospective at the British Film Institute.

The transformation of Eastwood from knuckle-dragger to darling of the critical establishment is one of Hollywood's most curious phenomena. In his prime, back when he made a trio of spaghetti Westerns for Sergio Leone, Eastwood was Ayn Rand's übermensch made flesh. He was the antithesis of Gary Cooper in High Noon. Instead of serving the community, he looked after number one.

In the 1968 presidential election he supported Richard Nixon and, as if to underline this, went on to make a second trilogy of films even more right-wing than the first. The message of the Harry Callahan movies is that liberal politicians, with their concern for suspects' rights, have made it impossible for the police to do their job; only a tough throwback like Callahan can protect the public. In a pivotal scene in Dirty Harry, we actually see him torture a suspect to discover the whereabouts of a kidnapped woman.

However, as a director, Eastwood has drifted to the left. Mystic River, his 2003 film, portrays the Boston police as fallible, with the principal suspect being innocent of the crime he's accused of. Eastwood followed this with Million Dollar Baby, in which he made a compelling case for euthanasia, and then came two iconoclastic films about the Second World War. In the first of these, Flags of Our Fathers, he debunked one of the central myths about the war in the Pacific, and in the second, Letters From Iwo Jima, he expressed considerable sympathy for the Japanese.

Eastwood has gone from being the Man With No Name to the kind of person who holds a placard and shouts, "Not In My Name." Dirty Harry's sins have been washed away and Eastwood has been embraced by the critics. In Hollywood, as in heaven, there is more rejoicing over one repentant sinner than there is over 99 who need no repentance.

The Clint Eastwood retrospective is at BFI Southbank, London SE1, until 31 August