And yet, to my mind, the sun will fade soon enough for our PM. There are three main reasons to think that any bounce will be limited in duration and size. First, the fact that, once all the numbers have been picked apart, Brown's "historic deal" will be revealed as a sham. Much as with one of Brown's Budgets, it takes at least a few days - if not weeks, months - for the charade to be picked up on by all the media, and to become the dominant narrative.
And then there's the question of whether the British public will really care about Brown's global endeavours. The PM has much to deal with on a domestic front - and I don't just have the recession in mind, although that's the biggest issue. Second homes, porn films and what Lord Myners did or didn't know threaten to bring Brown back down to earth with an almighty crash. Public resentment will not have been ended by the London Summit.
Finally, and relatedly, there's the simple fact that things are going to get worse in the UK. With jobs being lost, homes being repossessed and businesses closing, I imagine people will look on Brown's "New World Order" with even greater cynicism. And the Tories' "Labour isn't working" message could resonate more than ever before. So, while Brown may be enjoying the plaudits he's getting at the moment, the vultures are still circling above his premiership.
P.S. Tim Montgomerie writes on the same theme here.