I am a US citizen, currently living in the UK on a tier 4 visa. When it expires (March) I want to leave & then re-enter UK as a Tourist for a period of less than six months, to visit family and go to some weddings of friends that I have made here. I understand that as a US citizen I don't need a visa for this purpose, but my question is whether I have to go back to the US to re-enter, or whether instead I can travel to somewhere closer (e.g. France) before re-entering as a tourist?