Anakin Skywalker turns to the Dark Side in this final part of the Star Wars prequel trilogy Star Wars Revenge Of The Sith represents crucial closure for a particular wing of the thirtysomething generation. Their childhood was illuminated by Star Wars and they have been carrying a torch - or battery-operated lightsaber - for it ever since. Well, it‘s time to pack up the action figures and put them in the attic. With this final instalment in the trilogy, such wistful nostalgia gets not what it wanted, but perhaps what it deserved.

Star Wars Revenge Of The Sith is not just a bad movie. It is a video game you cannot play. It is a self-indulgent waddle through its own mythology. Unlike the other two prequels, it does not even have the veil of innocence to hide behind. Featuring the casual slaughter of children and climaxing with the grisly dismemberment of a main character, Revenge Of The Sith is a Star Wars movie that is not suitable for kids. So who is it for? Grown-ups? Really? Or just the masochistic adults who want to subject their inner child to another beating from Lucasfilm?

The prequels are about how Anakin Skywalker (Christensen) becomes the evil Darth Vader. Ultimately, this is a difficult story to tell, in which our hero becomes seduced by power, fatally flawed by his passionate attachment to the people he loves. In the cold special effects-obsessed hands of George Lucas, it is human drama as told by someone who appears comfortable with neither. Anakin was upset by the death of his mother in Attack Of The Clones and here he is upset by a dream that suggests his pregnant wife Padme (Portman) might die in childbirth. And this is our tragic hero‘s fatal flaw? That he loves people? It‘s the kind of story psychopaths read to their captives at bedtime. "Don‘t ever make the mistake of caring for people because if they die, you‘ll want to murder everyone in the universe." George Lucas‘ reputation as a people person is not enhanced by this insight.

Anakin is also a bit proud of his talents, and we all know how pride leads to a fall. By casting the unlikeable Hayden Christensen as Anakin, Lucas hoped to tap into the actor‘s whiny power to show us the danger of arrogance. As his great performance in Shattered Glass showed, Christensen is not necessarily a bad actor. However, when it comes to Star Wars films, you have to give him the benefit of the doubt and say, maybe something has been slipped into his soup.

Christensen‘s every line, his every gesture, his every look is a spear straight to the heart of your suspension of disbelief. His expression of deep inner turmoil is the look of a man struggling with mental arithmetic. The love scenes with Padme are awkward amateur dramatics in which no-one escapes with their dignity. Poor Padme spends the entire film in a kind of airport waiting lounge, passive, pregnant and dithering. Gone is the self-possessed political attitude of the first two films - now Padme‘s remaining talent is in selecting flattering backdrops to her evenings of hair-brushing.

Whenever human beings gather to exchange vows of eternal love or merely to swap exposition, the film stops dead. It grinds to an utter halt. In the background, there will always be a fiddly tableau of spaceships; in the foreground, there will always be two actors who follow their lines with peculiarly hunted expressions. Anakin becomes caught up in some office politics between the Jedi Council and the Senate. "I feel lost," he says, one of a number of occasions where the actors express the audience‘s doubts. "I want more and I know I shouldn‘t," he adds, as if Padme were offering him the second tier of a box of Milk Tray. The real Rebel Alliance is the twinkle in Ewan McGregor‘s eyes. Look at him when he says "I can‘t watch this anymore". Ditto Natalie Portman‘s mischievous "I don‘t believe what I am hearing," or the moment when Samuel L Jackson‘s Mace Windu offers a metatextual critique of the whole sorry enterprise: "Our worst fears have been realised."

Strip away the over-elaborate battle scenes and fiddly special effects and you are left with amateur dramatics, a script made of lead and all plot eventualities pre-ordained by the fact that these are prequels - we already know how this film turns out and no one at Lucasfilm has the wit to make the journey interesting. The only ideas on the whiteboard are another lightsaber battle, another computer-generated Charge Of The Light Brigade. Ian McDiarmid‘s performance as the malign Senator Palpatine is a searing addition to the series, but as for the rest, you‘ve seen it all before.

This time we get a cyborg called General Grievous who wields four lightsabers at once, for about a minute, before he gets two of his arms chopped off. This is a revolution compared to Count Dooku (Lee) who wielded two lightsabers simultaneously in Attack Of The Clones and obviously light-years away from the long lightsaber staff swung around by Ray Park‘s Darth Maul way back in The Phantom Menace. The Jedis are right butterfingers when it comes to their lightsabers. They also have trouble with ledges, which they are forever hanging off by their fingertips. (Although the Jedi can fly through the air, they are particularly susceptible to ledges, the presence of which - like Kryptonite - suspends their normal powers.)

As passion leads to the Dark Side, the Jedi make for boring heroes - their zen detachment only adds to the sense of tedium as the actors slash their way through more imaginary enemies. Ewan McGregor‘s Obi-Wan Kenobi cuts through robots the way Delia Smith dices a carrot. Cluttering the frame with zooming bric-a-brac and zipping lasers only adds to our indifference: the action sequences have no focus, no consequence, no point. The audience squints, wanting to be part of it all but beset by a nagging feeling of exclusion. The special effects are fighting again, dear, and there is nothing we can do to stop them. If you go to see this film, and find yourself whistling in the dark, here are a few questions to distract you from the abomination on the screen; why do the Trade Federation representatives sound much less Japanese here than they did in The Phantom Menace? Does this mean there will be Special Edition where the distasteful racial stereotypes of the first prequel are revoiced out? Why can everyone suddenly zip from one planet to the next as if they were merely stops on the London Underground? Why can the Jedi sense one another‘s presence across the vacuum of space but not when one of them is hiding in a cupboard? Or even miss the fact that someone is seven months pregnant? Why does it take around 18 years to build the Death Star? Trouble with the unions, perhaps?

But one question most of all: in the future, will there be a Special Edition of these films in which George Lucas is digitally removed from the director‘s chair?