Yesterday, after waiting for them to get something the right size in, I bought a refurbished bike from the Oxford Cycle Workshop around the corner. I was very happy with the purchase, and put it next to C's bike at the back of the house. This morning when I got up it had been stolen.
I hadn't locked it up as the D-lock I have wouldn't go around the bike shelter pole - I figured I'd get a chain lock today - and C had been leaving her bike unlocked for months without a problem. But I had been warned by everyone about the bicycle thieves in Oxford, and it seems they are both discerning of quality and very quick off the mark. That's a lesson I won't forget! (I actually had a thought just before I went to sleep that I should have used the D-lock around the wheel, though with half-asleep logic I was worried about the wheels being stolen.)
I've reported the theft to the police - who were very friendly and efficient - and there is a number engraved on the frame, but I don't hold much hope for ever seeing it again, even though my sister says they once got a stolen bike back.
Friends of ours had a brand-new barbecue stolen from their back yard the day they bought it, so opportunistic theft is obviously a problem. On the other hand, not a single house in this area has bars on the windows - unlike where we were in Sydney, where half the houses or more did - so break-and-enter must be a lot less common. (Possibly there is some kind of building regulation prohibiting bars, as it seems extraordinary that no one at all has them.)
Update (August 2011): Oxford Times story on bicycle theft hotspots