In the opening scenes, David and Jack reveal they are in northern England, and all the locals speak with Yorkshire accents. Yet the terrain is far too mountainous for Yorkshire (the scenes were filmed in Wales).
The small boy in the zoo is in his school uniform, but based on the previous scene it must be a Sunday. This is assuming anyone would really be cruel enough to make their child wear school uniform on a day out to the zoo.
Repeated mentions of werewolf attacks during a full moon are ignored when David undergoes his transformation on two consecutive nights. There is only one full moon during a lunar cycle. If the moon is full on a Saturday night, for example, it cannot be truly full on the next night, Sunday.
When we see Jack in his final state of undead in the porno theatre with the rest of the people he killed, when talking to David he uses a lot of words used that are formed with the lips such as 'schmuck'. However, Jack is virtually skeletal and has no lips to form the words.
It would seem extreme to take a badly injured patient all the way from Yorkshire to London - a journey of some 200 miles - when St James' Hospital in Leeds would be a lot closer. That is, unless the parents requested their son be taken to a hospital in London, due to ignorance of UK geography or assuming a hospital in the capital would provide the best treatment. Either that, or the locals felt it would be much safer to get David as far away from them as possible.
When David and Jack are walking on the moors, their shadows are always in front of them, despite them having changed direction numerous times. Additionally, with the moon always being behind them, how are their faces being lit?
When Doctor Hirsch is reading the newspaper about the murders, the first paragraphs of the news story relate to the murders, but the following paragraphs (in smaller font) relate to a completely different story (demonstrations by the New National Front).
When David is watching TV before his transformation, he sees a contemporary advertisement for The News Of The World, which is trumpeted as being available "tomorrow". The News Of The World only appears on Sunday, yet when Dr. Hirsch buys a newspaper the next day, after the night of mayhem, it is clearly a weekday edition.
During the Piccadilly Circus massacre, a side shot of the werewolf reveals part of its puppetry mechanism (a slightly large metal rod jutting out from its stomach). A foot from one of the puppeteers is also visible.
The villagers probably considered shooting David to sever the wolf's bloodline and end the curse; however, it would have been very difficult for them to explain to the police why they'd killed the victim of the attack as well as the assailant.
When Gerald Bringsley is running from the werewolf and trips on the escalator on the long shot down the escalator where it shows the wolf come in there's a clock above the escalator. Though the scene is supposed to be set at night the clock shows the time as being 13:01.
During the Piccadilly Circus car crashing sequences, a fawn colored car skids and sandwiches a policeman between itself and a red car. The safety barrier for the policeman (stuntman) can be seen before impact.