About 10 years ago my then-wife left me for one of my best friends, which wasn't a cause for wild celebration. In fact, it altered my plans so radically that, in a very public place, I threatened to kill him. I suspect that he didn't take the threat too seriously, firstly because I'm a fairly placid and rather squeamish bloke with an aversion to guns and ammo, but mainly because of the context. I was experiencing loss, betrayal and anger, and even in combination that stops well short of murderousness. So he, and everyone else within earshot, made the reasonable decision not to call the police.

Paul Chambers, a trainee accountant from Doncaster, became cross back in January when his local airport closed due to bad weather just before he was due to fly to Belfast to visit a girl he was keen on. He expressed his frustration by posting a message on Twitter: "Crap! Robin Hood Airport is closed. You've got a week and a bit to get your shit together, otherwise I'm blowing the airport sky high!" Several facts indicated that his intentions were benign, not least that he posts using his full name and helpfully displays his photo and his hometown, which hoaxers and terrorists tend to avoid. And the message would have slipped into the ether, had an airport duty manager not done a casual Twitter search for "Robin Hood airport" some five days later. Over the ensuing weeks there followed an unlikely sequence of events akin to someone incorrectly calling the toss of a coin 30 times in succession. The duty manager, airport security, Special Branch, arresting officers, the CPS and finally a judge all appeared to ignore the context, instead deciding that Chambers deserved punishment for posting a menacing message. That punishment was handed down last week: a £1,000 fine and a criminal record that has ended his career as an accountant.

Legal bloggers have become very exercised over the intricacies of this case, and almost unanimously agree that it's a disgrace. Online opinion is slightly more divided; on Sunday, following the re-closure of the same airport, thousands reposted Chambers' original message to demonstrate their solidarity, but others have openly criticised him for either being stupid, or not funny. But Chambers never claimed to be a comedian, merely a fallible human being using the internet. Detractors may scoff, but Twitter, Facebook et al are becoming extensions of our personalities, and using these services to express ourselves is becoming as instinctive as ranting down the pub, or bitching with a fellow shopper at a supermarket checkout. And the judge's obvious lack of familiarity with online interaction ultimately led him to make a flawed decision.

It was established very early on that Chambers posed no credible threat, so from that point he became the fall guy whose conviction might provide a warning never to digitally express your emotions using hyperbole. But it's not working. Right now on Twitter I can see threats to the lives of Lady Gaga, a dog called Sammie, and – thanks to the opening line of a certain Betjeman poem – the entire town of Slough. If the CPS believes that semi-public messages between friends that appear menacing – regardless of intent – should result in prosecution, they're going to be awfully busy. Chambers, by all accounts a mild, unassuming chap, has been encouraged to appeal by lawyers ("I just don't want to make things worse," Chambers said to me last week) and a fund has been set up to support him:


Along with Xbox 360s and Rubik's Cubes, mobile phones have now been banned from David Cameron's weekly cabinet meetings. While this could conceivably have been prompted by an ear-splitting N-Dubz ringtone favoured by William Hague, it's more likely to be an issue of "workplace incivility" that's been identified and explored by Christine Pearson, professor at the Thunderbird School of Global Management in Arizona. According to her research, nearly all of us think that using phones during meetings is rude, but two-thirds of us do it anyway. And the excuse we often give – that we're increasing productivity through multitasking – doesn't wash with neuroscientists. "Dividing attention between competing stimuli makes us less efficient," they say; all we're really trying to do is escape the room without physically leaving it. So Cameron's right: nothing's more likely to ruin a fragile political coalition than intimating that the Home Secretary's opinions are less important than your iPhone, no matter how true that might be.