When I was nearly 13, an older friend sent me a letter with “This is a bomb!! Do not open!!” scrawled in teenage handwriting all over the envelope. This attracted the Royal Mail’s attention – it was during the IRA’s letter-bombing campaign – and my friend got a telling-off from school. But as far as I know, nobody at the time was calling for the postal service to be closed to stop real bombs being sent.

Yet last week, as civil unrest in England mounted, so did calls for the suspension of BlackBerry Messenger – the chat medium of a new generation of teenagers – and curbs on Twitter, Facebook and social media. David Cameron, the prime minister, said he would “look at whether it would be right” to limit communication by thugs, rioters and looters via such services.

I think it would be wrong, and even if it were right, it would be ineffective and potentially counter-productive. Ineffective because these days plenty of alternative distribution channels are available. Counter-productive because social media and message services are also a conduit for good deeds – the most frequently cited being the tweeted calls to clean up after the UK riots.