To spoil or not to spoil, wonders DONALD CLARKE

Spoiler alert. Here be spoilers. Fans of this internet thing will be familiar with the concept of the spoiler warning. These words announce that a writer, aware that the reader may not have seen a film under discussion, is about to reveal significant elements of the plot. Don’t go flaming me, DarkKnight3456. You were warned that I was in bean- spilling mood.

Screenwriter recently got in a spot of trouble for, without warning, dropping what some readers regarded as a spoiler into his review of Zombieland. About halfway through that diverting (ahem, spoiler alert) zombie film, the fleeing humans take shelter in an initially unnamed celebrity's house. They have barely settled in when Mr Bill Murray, apparently now a member of the undead, lurches unsteadily in their direction.

To me, the Murray cameo did not seem a significant enough surprise to worry about, but at least two readers disagreed and sent this writer peeved (though polite) messages of complaint.

This particular plot point has divided reviewers. Two weeks ago, Boyd Hilton and Nigel Floyd, standing in for Mark Kermode on BBC Five Live's Simon Mayo Show, argued for five minutes as to whether this cat should be let out of its bag. The critic Roger Ebert mentioned Murray. The New York Timesexplicitly stated that it would not reveal the identity of the celebrity cameo.

One man’s huge reveal is, it seems, another man’s insignificant incident. When reviewing Duncan Jones’s Moon in this paper, I was careful not to say (spoiler alert redux) that Sam Rockwell’s character gets to meet and befriend his own clone. However, some reviewers felt that, as the incident happened early on in the film, it was fair enough to include it in their review.

All of which proves that no firm etiquette has been established in this area. It is fairly clear that people will get upset if you behave like one of those old-school, high-brow critics who regarded it as their duty to describe the film’s final scene. “Discovering that Marcel’s parrot was the killer was the most jarring experience of my career as a critic,” Dominique Le Frou Frou might have written. Conversely, only a buffoon would complain when a critic reveals that 2012, the latest Roland Emmerich opus concerns a global catastrophe.

At the risk of further infuriating those already fuming at Murraygate, it should be acknowledged that any piece of critical writing is bound to reveal significant elements of plot. Note, however, that every film worth seeing will stand up to a second viewing when all the major story points have been well and truly “spoilt”.

So, henceforth, you can assume that the phrase “mild spoiler alert” hangs somewhere between the newsprint and your face.

You will not, of course, actually see those words on the page. It’s a horrid, clumsy construction that doesn’t belong anywhere near ordered, grown-up prose.

Hey, you didn’t see that coming, did you? Well, not unless someone spoilt it for you.