Imagine Sir John Betjeman was still with us and, like that other national treasure Stephen Fry, had become a fan of Twitter.
Imagine him now sitting down and cheerfully beginning to tweet to his devoted followers a much-loved poem.
"Come friendly bombs and fall on Slough!" he starts.
Now imagine some security officer at Slough council, doing internet searches.
He or she comes across this tweet.
The tweet is immediately passed to special branch; and special branch decide to send a squad of dedicated and trained anti-terrorist officers to Betjeman's undoubtedly idyllic semi-rural home.
There is then a knock on Betjeman's door.
The squad of anti-terrorost police then arrest Betjeman and, in front of his bemused family and neighbours, march him to the police cars.
It gets worse for our former poet laureate.
For, although the anti-terrorist police do not see the tweet about Slough as a credible threat, it is referred to the Crown Prosecution Service.
The CPS quickly realise that Betjeman cannot be prosecuted under anti-terrorist legislation or the specific bomb hoax offence; but they decided to prosecute him anyway, using an obscure provison in telecommuinications law - section 127 of the Communications Act 2003 - which hitherto had only been used for offensive telephone calls and messages.
After all, their reasoning goes, a message sent over the internet is also a message sent over a public telecommunications system.
The CPS turn up to court and tell the judge and the defence - wrongly - that intention is irrelevant for this offence. Betjeman is reluctantly advised to plead guilty.
Betjeman is asked by the judge to stand, and he hangs his head in shame as the sentence is read out.
Sir John Betjeman has now a criminal record, and just because he tweeted: "Come friendly bombs and fall on Slough!"
Absurd?
Well the above is the logic of the CPS position in the Paul Chambers case, whose conviction under section 127 is being heard by Doncaster Crown Court on Friday.
Paul's tweet, sent as a joking statement of exasperation to his followers after realising he would not get to stay with a new girlfriend, was:
"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!"
Not perhaps as elegant as Betjeman's first line, but it does share the following features: a specific target (Robin Hood Airport/Slough), an exclamation mark, and the prospect of a bombing exercise.
As a matter of legal analysis, the CPS position on someone who tweeted Betjeman's line cannot be distinguished from Chambers' ill-conceived comment.
They both would be "menacing communications" under section 127.
And so would any "menacing" comment sent by anyone by email, or put on a blog, or loaded onto YouTube; indeed any content sent over the internet whatsoever.
So, this Friday, it is not only Paul Chambers in the dock: it is also the ghost of Sir John Betjeman.
And it is all of us who have ever sent content over the internet which some person at the CPS can somehow deem "menacing" and so commence the horrifying and inescapable bureaucratic procedure which lead to the imposition of a criminal record for simply making a light-hearted comment.
This cannot be right.
So if you are on Twitter at 10am on Friday, why not tweet "Come friendly bombs and fall on Slough!" in support of Paul (hashtag #TwitterJokeTrial) as his appeal begins.
For if we are all now to be done over by anti-terrorist officers and the CPS for comments of such a nature, we may as well all go down quoting Betjeman.
David Allen Green blogs on policy and legal matters for the New Statesman and was shortlisted for the George Orwell Prize in 2010. He is also head of media at City law firm Preiskel & Co, who are assisting Paul Chambers and his criminal lawyers pro bono in this appeal.
So if you are on Twitter at 10am on Friday, why not tweet "Come friendly bombs and fall on Slough!" in support of Paul (hashtag #TwitterJokeTrial) as his appeal begins.
