Sci-fi thrillers are 10 a penny now but those based on novels by legendary futurist Philip K Dick are normally worth taking a bit of notice of.

After all, he's the writer behind Blade Runner as well as Total Recall and, if the makers stick to the book, we don't have to suffer the usual cliched Hollywood-style ending.

It's 2079 and revered government scientist Spencer Oldham (Sinise) and his hospital doctor wife Maya (Stowe) are just back from holiday and about to throw themselves back into work refreshed.

However, as Spencer strolls into the complex where he builds weapons of mass destruction, he's waylaid by government spook DH Hathaway (D'Onofrio).

Hathaway is convinced Spencer has been cloned by humankind's alien nemesis and is, in fact, a walking, talking bomb primed to assassinate a senior government figure.

Spencer, as you might expect, sees things very differently... but he has to get to his hospital records to prove he's bona fide flesh-and-blood and not a replicant.

However, Hathaway does not merely suspect Spencer but has already decided he's an extra-terrestrial stooge and must be eliminated at all cost.

The chase is on and Spencer does pretty well for a boffin - dropping down lift shafts, slipping through vents and making his way down disused service tunnels.

Pretty soon he realises he isn't going to make it on his own and hooks up with underground rebel Cale (Mekhi Phifer), a streetwise hustler who needs to get to the hospital for medical supplies.

Together they are pitted against Hathaway and his goons... but it's difficult to tell who are enemies and who are allies as the stakes get higher.

While nowhere near as visionary as Ridely Scott's Blade Runner, this still has enough genuinely disturbing ideas and plot twists to keep the attention.

The casting of an everyman actor such as Sinise makes sure celebrity doesn't get in the way of the character but he never quite engages as the desperate quarry.

Tim Evans