Yesterday, the Prime Minister of the United Kingdom, head of Her Majesty's Government, became the first head of government (at least, as far as I can tell) to officially embrace Twitter.
Is this a momentous occasion? It's hard to say. Politicians have been increasingly embracing various forms of social media. Nowhere, for example, do more elected officials actively write blogs than in Europe.
Some have suggested in recent days that Twitter is going mainstream. Perhaps that's the case as well.
The 10 Downing Street Twitter is using Twitterfeed to publish news from the 10 Downing Street website's news feed. They also have one tweet that was entered directly here.
Stuart Bruce appears to have been the first to report this on Twitter. He has also blogged the news.
The U.S. government is behind the UK when it comes to Twitter. There are some U.S. congressman on Twitter - see here, here, here, here and here. The U.S. State Department has a Twitter here for its Dipnote blog but the White House doesn't have a Twitter.
Update: Online Journalism Blog says it was Dave Briggs who first tweeted about the Downing Street Twitter not Stuart Bruce. Briggs beat Bruce by a little over an hour according to Tweet Scan.