Yesterday my wife arrived at her office without her ID - not that she has ever had to show it, up to now. The security guys know her by name, largely because she holds a senior position and is usually the first to arrive and the last to leave the office.

But there had been an attack at Glasgow airport, on the other side of Scotland, and the  threat level was 'critical' so, naturally, security had to step up their vigilance.

This increased vigilance manifested itself as a  requirement to sign the visitor's book. (That'll keep 'em out). In the space where it asked for the name of the person she was visiting she wrote, 'myself'. It seemed to throw the guys for a moment, but the penny finally dropped and she was permitted to enter the building. Phew!