It happens that it was sent in by Rob Fenwick, a Lib Dem and Simon Hughes supporter.
Rob's own blog gives a transcript of what happened:
The last thing Ming should do if he wins the leadership is sell his Jag.
SKY: Let's talk about the environment, an important issue that Lib Dems certainly put at the centre of the ground. This question from Rob Fenwick: "Both Ming Campbell and Chris Huhne claim that the environment is of paramount importance. Chris Huhne owns a hybrid electric car, a Toyota Prius. Is it correct that Ming Campbell owns not one but TWO Jaguars? And if so, how does that square with a supposed commitment to the environment?" A gas guzzler, Sir Menzies
CAMPBELL: I have one 20 year old car which has been my pride and joy.
SKY: Not the best for the environment.
CAMPBELL: But we are all going to have to change our habits, including me.
And then later:
SKY: So the jag goes, does it?
I see it as central to what could be a very popular image. He would be the new Inspector Morse or the sort of dependable Scottish lawyer who was always played by Iain Cutherbertson.
Don't do it, Sir Menzies.