I stepped off the tube at Bank Station on Tuesday and thought of 2 things: That I’m hot. (Not, I’m afraid, a Bradley Cooper or even Scarlett Johannsen hot – more a “middle-aged man in a suit on the tube on the hottest day of the year” hot). Oswald Laurence. You may not know Oswald, but you may have heard him. He made one of the original “Mind the Gap” recordings – the iconic polite but firm instruction heard at tube stations throughout London.