Not a single day goes by for me without my mind drifting back 54 years to remember the seminal event of my life: the occupation of Czechoslovakia by the armies of the Warsaw Pact, led by the Soviet Union, and my subsequent exile. I was going to use the phrase “I cast my mind back” but that would be misleading. I don’t need to “cast” anything. It’s an automatic thought. Sometimes I dwell on memories of those days for a while, often I don’t - it might be just a flash, a mental snapshot of myself at 15, walking down towards Prague’s commercial center, Wenceslas Square”, and staring directly into the muzzle of a tank with a red star on its side.