Remember that speech the Prime Minister uploaded onto YouTube last week, in which he advised the nation how he was going to tidy up the mess on MPs expenses? Probably not, because while 4,000 or so browsers clicked on to Gordon Brown's video from Downing Street, more than 100 million opted to watch Susan Boyle's instead.

So if you were among those who didn't, then you missed its most arresting aspect, which was that No 10 censored the traditional prerogative of YouTube surfers to post comments on what they've seen. “Adding comments has been disabled from this video” reads a note beneath the broadcast. Did nobody in Downing Street spot the irony? That a video proposing transparency in MPs' finances in the name of democracy and open government was itself suppressing open democratic debate on such proposals?

But Gordon Brown hadn't calculated the physics of it. When you plug one hole in a dyke, the water gushes all the more forcefully from the next exit it can find. Which may explain the comments posted on non-official YouTube copies of Mr Brown's video. “This sounds like balderdash,” reads one. “The category of this video is titled 'News and Politics' when it ought to be comedy,” reads another. But some are supportive: “Short and to the point!” No, wait. That was a response to a preceding comment, which urged Mr Brown to do something anatomically uncomfortable.

The internet is a fiercely democratic medium, available to all, allowing anyone to say what they want to say; even if it is occasionally scary what they do want to say. But the test of democracy is freedom to criticise. Evidently, what Mr Brown craved was a pulpit rather than a conversation.