But all stories have a moral purpose. In praise of Guy Fawkes, the Wachowski brothers are with George Bernard Shaw, declaring that the moral choice is to choose revolution, and the moral life is committed to revolution, and corruption breeds in the stagnation of the status quo.

The character V at first comes across as a nearly comical comic book hero. He wears a black cape, a broad hat, a brace of glistening silver knives holstered across his chest and a Guy Fawkes mask. He delivers, in a rich English accent, a kind of random outpouring of elliptical sentences and grand vocabulary, like an actor who has swallowed Bartlett's Quotations and a copy of Word Power. He looks and behaves like the sort of comic book hero created by someone who keeps discovering that all the good superhero attributes have already been scooped by Superman, Batman and the Silver Surfer.

This doesn't seem like sure footing for an exploration of moral purpose in life. For a nervous quarter of an hour at the beginning of this longish (two-hour) movie, it flirts with being too silly to sit through.

However, having established the improbable hero and the bare bones of an unlikely but morally piquant near future, the filmmakers are quick to muddy the waters, morally speaking. The mud is more subtle and sophisticated than the silly grinning mask.

The England of the movie is not so much a fascist dictatorship as a theocracy lacking theology. Instead of any sort of cracked conception of a limited, vengeful God, the new regime under the High Chancellor reinforces a sort of drugged apathy in the populace with fear. Fear (of the unknown, of chaos, of unpredictable thought) is the orthodoxy which admits each Englishman to citizenship. Against this background V is a terrorist.

At first it's the sort of fun terrorism that's easy to cheer for. He blows up buildings, spectacularly, to the tune of the 1812 overture. No blood is shed. His target is a jail. The only teeth set on edge are in the heads of state. His secret underground lair is stocked with books and art (most of it of a convincingly Catholic, counterreformation bent). He comes across as the last civilized man standing up to a brutalized state.

By and by, V is revealed to be no less averse to shedding blood than the black clad, faceless secret police. Nor are his targets always clearly deserving. The innocent die. The audience will cheer, but some will feel guilty for cheering.

Neither is Finch (Stephen Rea), the police detective who chases V, some automaton of the state. He is a careful man who wears his weariness the way a knight wears shining armour.

We learn that the masked man derives his powers and purpose from a series of experiments on human subjects conducted in a secret jail by a doctor willing to suppress her conscience for scientific rewards. The state, church, pharmaceutical industry (and thereby capitalism) and science are complicit in torturing V into existence.

"What was done to me was monstrous," explains V. "And they created a monster."

Then we learn that our hero is capable of exactly the sort of manipulation of another human being as the regime has used to create a fearful populace.

This leaves V's accidental ally Evey (Natalie Portman) lost, unable to entrust her allegiance to anyone alive. She lives a year underground and alone, in the classic manner of revolutionaries. She must ultimately choose between V the terrorist and a terrorist state. Thanks to V she has learned to shed the orthodoxy of fear, but at a cost.

In the end we're back to fireworks and the 1812 overture and an England populated by defiant, unbowed people. What could be more fun than watching Guy Fawkes' plans finally reach their glorious fruition?

The most interesting thing about giving this fictional revolution an injection of DNA from Cromwell's brutal theocracy, and the fumbled and stillborn Catholic revolution, is that it was in 1607 a battle not between freedom and a cruel order, but a conflict between theocracies. There is little evidence that Bloody Mary's regime would have been sweet or forgiving.

When V for Vendetta slips real news footage from Iraq into its fiction, it reminds the audience of how we find ourselves dragged along between the severe, fundamentalist forces of Islamic-inspired terrorism and the Christian fundamentalist extremists in charge in the White House.

Perhaps the more telling image of revolution in V is borrowed from the Bible. When V survives the experiment that killed all its other subjects he emerges from an inferno. This repeated image of the man standing defiant in the middle of the fire can't help but recall the picture of Azariah, Meshack, Shadrach and Abednego praising God from the middle of King Nebuchadnezzar's furnace (Daniel 3:19-97).

In the England that V defies, the regime's slogan is "Strength through Unity, Unity through Faith." But the truer test of faith is the whether you have the strength to defy an imposed orthodoxy.