Walked under the River Tyne where pedestrians and cyclists get separate tunnels. As a kid in the 1950’s, this was exciting especially after a friend of my dad’s told me they’d found a leek in the tunnel. Back then, shipyards lined the Tyne, and 20,000 people a day crossed here.
Maybe your friend was referring to the vegetable leak?
Leek v leak
Exactly! He was teasing six-year-old me. Here in the NE of England, leeks are taken seriously. I once visited a pub where leeks were piled on tables, ready for judging. I suspect leaks in the tunnels are also taken seriously.