The movie Doomsday is your average post-apocalyptic semi-end-of-the-world movie. Although I didn't have very high hopes for it it actually turned out pretty decent and in any case quite entertaining.
Scotlands is infected with the über-deadly Reaper Virus which leads Britain to isolating the entire Scotland area and shooting/burning/brutally killing anyone who nears the huge wall spanning across the land, actually along the same path as the old Roman Hadrian Wall. After a while people forgets about the whole incident. After some years however, the Virus re-appears but this time in London. They (the government) have noticed that people have somehow survived in the still isolated Scotland area and assume that is because there is some kind of cure for the virus somewhere. They send in a team to get it in a Scotland that has turned into barbarism and *gasp* cannibalism.
That is basically where the story takes off and there will be alot of action and near splatter like violence along the road. The main character, major Sinclair, is actually a quite interesting and likeable woman who definitely can take care of herself. She is played by Rhona Mitra who is doing the cool-as-ice thing well and you can tell the character is inspired by Snake Plissken as Wikipedia claims. The rest of the team consist of the random bunch of clichés and the movie is mostly about this team going from one major fight to another, always losing some men along the way. They've even tucked in Malcolm McDowell in a small but important role. The story is quite standard but the main character and an average good pace of events keep this movie up. It has an intro as if it really wanted to be about something else, something more serious. After some minutes it feels like the director went "Meh, screw this serious business, let's just let everything be really violent, everyone likes that". That is what this movie is all about. Some scenes are quite grotesque and some parts of the story don't really fit well together. If you watch it with the premise of simply wanting to be entertained by some simplistic violent action you won't be disappointed though.