A man arrives at Heathrow airport. He’s not a journalist, but someone carrying a mystery package for a friend. What he’s carrying could, by common consent, have huge implications for the national security of the UK if it fell into the wrong hands. By definition, the wrong hands could include terrorists.

What do we honestly expect the UK authorities to do? Give him a sly wink and say “off you go son, you have a nice trip”?

If we do expect that then, in effect, we’re saying anyone who manages to get their hands on our nation’s secrets should receive a guarantee of free passage, just so long as they say “Don’t worry. I’m taking this stuff to King’s Place”.

Alan Rusbridger’s piece is subtitled “As the events in a Heathrow transit lounge – and the Guardian offices – have shown, the threat to journalism is real and growing”. But as Alan Rusbridger himself then writes, “Miranda is not a journalist”.

When we all heard he had been arrested, we all thought “That’s a disgrace, why should someone be arrested simply because his partner works for The Guardian?” But that goes the other way as well. Why should David Miranda be allowed to happily saunter around carrying Britain’s most sensitive secrets simply because Glenn Greenwald is his spouse? Are we seriously saying the phrase “I’m with Greenwald” should now act as an international get-out-of-jail-free card?