I'm stumped! It's a mystery! What sort of plane is this?

Update: Time corrected to 12:21pm (my camera clock was not adjusted for daylight savings!)... and Cessna C525B, ZK-TBM was flying NZNR to NZQN at this time, so that fits. Thanks everyone for the updates on Twitter, Oz-spotters list and here!

Yep, it's true. I've photographed a plane and I have no idea what type it is! If anyone has any ideas, I'd love to hear them. This aircraft went over head Wellington [or just north of] at about 12:21pm this morning [Saturday 10 December]. We only noticed it because of the condensation trail behind it which was well formed, indicating low winds at altitude.

It appears to be a twin engined aircraft with a straight leading edge [so, not a Boeing or Airbus of any sort that I can tell] and probably at least 30,000 feet, possibly/ probably higher. The wings look quiet large compared to the body also, and it might have rear-mounted engines. Perhaps a business jet of some description?

Unfortunately, the plane being a stolen American surveillance drone being operated by the Iranians who are spying on us has already been suggested... no points for that one! [Iranians Capture US Spy Drone?] However, if you really believe it was the Iranians, then please send a stamped, self-addressed envelope to me with $50 cash and I'll send you a tin-foil hat. My address is... ummm... errrrr...... ok, just email me the cash :-)

Here's the picture. It's a bit fuzzy, but it's the clearest resolution I could do.