No idea (I just capitalized the "m" of "Movie"); I thought that you did, despite having mentionned "Custom Made" in your comment. Isn't it more likely made for the movie, was it is used in it?
Windscreen shape and angle matches the Bedford J well and these are unlikely to have been altered other than the false centre divison being added.
The bonnet and front wings also Bedford J - the narrow rear track would be J1.
However the chassis is less certain. Whilst the body is based on a Bedford the front and rear tracks and the ground clearance could suggest it was heavily modified or fitted to another chassis.
It's a Bedford cab, not so sure about the grill. The reason this truck looks so odd is that the Nova Sterling car is underneath it! If I remember rightly, the Bedford splits open and the Nova races off in a chase scene. Not a great movie but I thought that was a well thought out device.
I have recently seen some of the movie and the cab interior had a Bedford fascia and instruments. Although it would probably be a studio set-up for the interior, it does indicate they based it on a Bedford J type by using a fibre-glass replica of the cab, as Alexander said.