'Maybe? It's a possibility'
One of the most likely locations of Grand Theft Auto IV is London, England. While there is no new information or indication that the game is taking place there.
official website. Also, you can buy the PS One version or if you want the PC version, these eBay search results might be your only option.
London 1961 expansion for free. To see more information on the original London game, visit the GTA: London 1969 index page.