Peter Mandelson's appointment came as a complete bombshell. So far as I know, nobody predicted it. And it partly answers those Brown critics - of left and right - who have long said the Prime Minister should be much more inconclusive, and widen the ranks of his ministers politically. Certainly with Mandelson in cabinet it will be quite a lot harder for the Blairites to challenge Brown's leadership.
Peter Mandelson was due to step down as a European Commissioner next year, and had already started thinking of a new career in business. But the chance to return once more to cabinet was irresistible. In part, it brings what one friend calls "closure" to the huge sense of personal injustice he harboured over his second forced resignation - over the Hinduja passport affair - a resignation which most people in politics now accept was unfair.
Peter Mandelson returns to cabinet in much changed circumstances compared with his two brief spells in the early Blair years. He has established a new, independent reputation in Europe, where he is generally thought to have done well in the job of trade commissioner. Whereas in the past, his position stemmed simply, in the eyes of many people, from his closeness to Tony Blair. Indeed that was why so many in the media pursued him so relentlessly, helped to a large degree, of course, by key figures in the Brown camp. Presumably the latter will no longer be a problem.
It suggests a new attitude to government by Gordon Brown - a willingness to have colleagues around the cabinet table who will stand up to the PM when necessary. Among the previous team it was hard to see anyone who would do that. A return, perhaps, to the style of Attlee, Wilson and Callaghan, who happy to have fellow big beasts in cabinet who might easily disagree.
Which brings me to the strange story of Jon Cruddas, the left-wing MP who did so well in last year's deputy leadership contest. The word was that Cruddas would now be brought into government, perhaps as housing minister. But that job has now gone to Margaret Beckett. There's a strange silence from the Cruddas camp today, so something may yet happen, especially since not all the ministerial posts have yet been filled.
Beckett's return to ministerial office seems a pretty selfless act, for she's got a post which isn't even in cabinet (though she can attend cabinet meetings). And yet only 15 months ago she held the mighty post of Foreign Secretary. And previously she's been deputy leader of her party, and indeed was briefly, in 1994, Labour's acting leader.
Finally, a small amusing footnote. The posts of Scotland (Jim Murphy) and Wales (Paul Murphy) are now held by men with the same name, a name which is Irish.