Ask HN: Expat founders in the UK?

Does anyone have experience starting something as an Expat in the UK? Are the hurdles substantial? How do the entrepuener visa requirements end up working? Does the government need to see business plans and financials?

Im about to embark on a project, and trying to figure out if i should try where i live (London) or return to my country of citizenship (US). The project's target audience is not country specific, so i dont think that matters terribly.