Assuming that you have a good wired Internet connection, it should work fine.
You'll need an adapter to match the power plug to a UK socket.
If you'll be using a UK phone, you'll need to change some OBi settings to get caller ID working.
If using an old UK phone without a modular cord, you'll need an adapter to match its plug to the OBi RJ-11.
If you'll also have a landline in UK and want to connect it to the LINE port, you may need an adapter to match the wall jack, and/or some settings changes.