Showtime’s stateside Shameless incarnation has been widely praised by critics since its premiere in 2011, but a British version of the show had actually been around since early 2004. The premise is the same: Both versions revolve around the dysfunctional Gallagher family, who live in a working class neighborhood (Chicago on Showtime, Manchester on England's Channel 4) and try to get by in hilarious, often illegal ways.
It's no small feat that Shameless had managed to remain well-written and interesting in its 11 seasons. That's in small part due to the fact that, like many British television shows, new characters are often introduced and main characters—Fiona Gallagher (Ann-Marie Duff), for instance, who was the show's backbone in its earlier years—could be written out at any point before the writers get the chance to exhaust the plot and run out of ideas.
Plus, since censors and the FCC aren't concerns in the United Kingdom, Shameless had the opportunity to be as raunchy and outrageous as it wants—just as the show was intended to be.