A pernicious little virus has caught us in a trap with a catch-22 all its own. The film Catch-22, 50 years old this year, resonates with a time when contradictory choices seem necessary.

'A catch-22 situation' derives, of course, from the impossibly circular and wonderfully entertaining Joseph Heller novel of 1961, on which the film is based. It is a great read from beginning to end, even though the story starts in the middle.

It charts the dilemma of Captain Yossarian (Alan Arkin) who has been posted to a Mediterranean island during the last months of World War II. He is desperate to get out of the bombing missions he is being sent on into France and Italy.

Alongside him, new recruits, younger than ever, are getting killed on pointless missions. Sometimes they are killed before they even begin their tour of duty. What is the sense in that? It's a fair question.

The film's key scene where Doc Daneeka (Jack Gilford), explains to the squadron captain that claiming he is crazy to be released from duty would cut no ice, is as fresh as ever.

Because of bureaucratic regulations, there is no way for Yossarian out of the conundrum he finds himself in.

Director Mike Nichols had a dream cast besides Arkin to work with. Orson Welles was on board in a small role as a pompous general. Jon Voight is unforgettable as motormouth Milo Minderbinder, the profiteering mess officer, and Anthony Perkins, the creepy Norman Bates from Psycho cast against type, is the chaplain.

Art Garfunkel appears in his first film role as Nately, a good-natured 19-year-old. A conversation on nationalism that he has with an old man feels like it could have been written today, as the film gives full measure to the book's prophetic words. They hang in the air, full with irony. The film's screenplay was written by Buck Henry (The Graduate).

For its time, Catch-22 was very expensive to make, but the studio had so much faith in its director, Nichols, who had just had huge success with The Graduate and Who's Afraid of Virginia Woolf?

Cinematography by David Watkins and editing by Sam O'Steen are top class, but Catch-22 flouts a convention or two. It is like a series of disconnected, absurd incidents, strung together. The scenes are gems in themselves that accrete over time so that this dark, anti-war satire eventually makes sense.

From the moment Catch-22, begins the experience borders on the surreal. Dawn approaches with scattered bird song, and then the spell ends violently as a squad of B-25 bombers roar across the frame. The bombers were the very thing according to the production history.

Unfortunately for Mike Nichols, he was beaten to the post. Robert Altman's uproarious, frenetic anti-war satire M.A.S.H. came out in January 1970, and enjoyed huge success at the box office just months before Catch-22 opened the same year.

What a coincidence. You might think that both rode high on the anti-war sentiment of the times as the Vietnam War trundled on, but no, Catch-22 tanked at the box office.

Despite the no-expense-spared budget, audiences in 1970 may have got bored with the elliptical story-telling in Catch-22.

Or by the time they'd seen M.A.S.H. they may have felt that, as far as anti-war movies went, they'd seen it all. Yet both films are so very different.

It could be that for many people today the films Catch-22 and M.A.S.H. have merged into one long, indistinguishable anti-war epic.

When the book was published in 1961, it captured the futility and absurdity of war. Which war was that, exactly?

Joseph Heller had begun writing his landmark novel sometime in 1953 when the Korean War was settled, but he had actually set his story in the last months of World War II.

When the film of the book appeared in 1970, it was taken up by the Vietnam War generation.

Slowly, over time however, Catch-22 has managed to catch up with M.A.S.H. in the critical stakes.

A television series co-produced by George Clooney came out last year, but Mike Nichols' film is better than it, and a cut above M.A.S.H.