Utopia UK season 2 left off with a good cliff hanger, but there is a movie that actually works pretty well as a sequel to Utopia. It wasn't intended to, and it isn't perfect, but as long as you can accept a few things like the timeline being different, then Children of Men works great.

Here is how the two could connect storywise. First of all, Wilson wins and everyone gets vaccinated, but there was a flaw in Janus. Over the years it evolved and changed, leaving the entire world sterile. 18 years later, no one has even been born.

With that quick bridge, Children of Men works great as a continuation of the story and maybe even the end.