The music coming from the mobile phones further up the carriage was loud and tinny. It was the middle of the day and the train, creaking and groaning on its way from south-east London to Charing Cross, was only a third full. I managed about three stations before walking the few steps to where they sat: two very tough-­looking girls in their late teens. The adrenalin pumped.

“Excuse me, but would you mind turning it down just a bit, please?” I asked with the most ingratiating smile I could muster. They carried on, seemingly oblivious. I tried again, and then again. Finally they looked up, shocked, and then, almost immediately, angry. “Not doin’ you any harm!” one of them blurted at me. “What’s it to do with you? No one else has said nothing. Oi, mister” – she got the attention of a young guy sitting a few seats away – “we ain’t bothering you are we? You don’t mind, do yer?”

The man looked vaguely in their direction, and then up at me standing, and smiled with what seemed like the hint of a derisive snort before turning his gaze back to the window. “See! He don’t care. Thanks mister. What’s your problem?”

I looked over at the man. Yes, mister, thanks a lot. I turned back to the two girls. “It’s a public place, I’m just asking you nicely to turn it down a bit.” But if I ever had them, I had lost them now. It was obvious that my use of the words “public place”, combined with the fact that I was wearing a suit that day, marked me out as a stiff who could be dismissed. And nobody else was backing me up. They duly carried on.