Travel panning

Other than getting testy with sloppy reporting, I am a bit intrigued as to what guides or 'leaders' travel plans. Whim? Whimsy? And who pays for all these mercy dashes of questionable public benefit?

Prospects for Tuesday, 10 JuneNewsnight
Today's output editor is Simon Enright - here's his morning e-mail to the production team:
Tomorrow sees the crucial 42 day parliamentary vote and David Miliband has cut short his trip to fly back today to help lead the debate.

I'm sorry, but as I don't know as much as I evidently am expected to, maybe someone might help with explaining what trip and where, and why he was there and now needs to come back to 'help' 'lead' this debate? Was he on holiday? Or on UK business? If so what is happening to the overseas responsibilities in the interim. Is he going back? I am a little confused as to how all this gadding about works. Was the date a last minute surprise to the diary? Is his presence essential? Who pays?

I am not, of course, expecting too mnay answers.

I am sure there are good reasons and explanations, but a lot seems to have been taken as read. Having been given a hint at the situation, it would be nice to know the full story.