Hi, I know in the past it was the case that I needed a UK based server to host my .net site to rank in the UK SERPs - in google at least. I would like to know if this is still the case. I'm hoping it's no longer necessary.
For a non-professional webmaster who just wants to create some content and not be distracted from the underlyuing business by too much techie stuff I would say use hosting in your own country every time. For a professional webmaster then aakk9999 says there are ways to geotarget your domain.
UK / US connections are pretty robust and the noise from other factors would probably mask any visible difference in connection times if you hosted in North America.
i assume your UK SERPs are for UK visitors. depending where in the US you're hosted and where in the UK you're surfing, you could easily have somewhere in the range of 150+ ms of latency due to the transatlantic transmission alone, so let's say you're adding a third of a second to every round trip. that might affect your user engagement compared to your locally hosted competitors.