4. Gang Warfare
London is notorious for its gangs and Rockstar has utilised gang warfare in GTA games before, most notably in San Andreas. Rockstar could use this as part of the story and bring back the gang fights in SA, where you had to kill the enemy gangs to control that area of land. Considering Londons size and multi-cultural nature, there is any number of gangs that could be created from hooded youths on council estates (just like in real life) to hard as rock tipped nails Russian gangsters. Each area you control would yield differing amounts of money, if you control Chelsea and Hammersmith, you will gain more than you would Brixton. While not exactly like the gangs like they have in America, here we have these vile parasites in Britain called chavs. These servile inbred scum are a cancer on British society who show no respect to the law or society, these horrid beings make GTA criminals look like saints; so you could take a break from breaking the law and being a nuisance to society and do something constructive and eliminate every chav you see, thus reducing the criminal population and making bus shelters safer for commuters. If you dont know what a chav is, Google it or go on encyclopedia dramatica and youll find out what these hideous beasts are.