...the best part of 35 years ago, I got "detained" in an empty office at Heathrow for about 90 minutes after returning from my first trip to the US.
On having my holdall searched, they found my copy of Chairman Mao's Little Red Book which they seemed to get a bit excited about.
After the 90 minutes, a bod came and apologised for the delay and let me out.
The fuckers stole my 10 cans of Coors Extra Gold, though, and my fags.
In any case, it was the last time I traveled with any "alternative" political literature.

This was at the time when they were going hard about the never leave your luggage alone at any time when you are flying, and I have to say, I got pretty nervous thinking about that as I waited in that room as I had indeed left my holdall alone, several times at JFK as I went for a pish after drinking a couple of beers at an airport bar.
Never did that again.