Braveheart meets quantum physics in the time-hopping adventure pic Timeline, based on a novel by Hollywood's favourite high-concept novelist, Michael Crichton. It has all the gormless idiocy of a high school science project done by Bill & Ted, as Paul Walker heads back to medieval France to rescue Billy Connolly's professor after an experiment with a new time machine goes badly wrong.

A shadowy corporation, run by a ruthless industrialist (David Thewlis), has inadvertently stumbled across a wormhole to medieval France while trying to invent a teleport machine. Wait, it gets even better: after archaeologist Professor Johnston (Connolly) is trapped in the 14th century, his son (Walker) and a team of fellow tomb raiders (including Frances O'Connor and Gerard Butler) high tail it after him, only to get caught up in a war between the English and the French.

Looking distinctly out of his depth - and his time zone - bleached blond beefcake Paul Walker is by far the movie's biggest liability, a walking vacuum in the time-space continuum with a terrifying ability to commit heinous crimes against cinema dialogue: "We've got 650 years of knowledge on these guys. If we put our heads together we can get out of here in 20 minutes". (Memo to Mr Walker: your village called, they're looking for their idiot.)

That alone would make this unexpectedly entertaining, but the presence of Richard "Lethal Weapon" Donner behind the camera ensures that the medieval battle sequences come with a healthy dose of tunic-ripping, swashbuckling action as castles are stormed, maidens are threatened (in particular Anna Friel's Frenchie damsel), and armies of battle re-enactment weekend warriors play soldiers.

Timeline is the kind of brain-dead romp that's so unintentionally hilarious, you're likely to crack a rib guffawing.