Amongst the people featured in the piece, there's a guy who said he fell madly in love with a stranger he saw on the Tube "she actually took my breath away", people who said they'd be too shy to chat up people, plus a guy who got married as a result of meeting someone on the Tube.
The producer, Mark, even managed to find one girl who admitted to making love on the Metropolitan Line, between King's Cross and Harrow on the Hill. She and her then boyfriend were in a carriage with eight other people in it (although they were both pretty drunk at the time). "After a bottle of vodka I really didn't care. Vodka's an evil thing, I can't say no", she said. Also the love making didn't appear to require a lot of effort: "It's surprising that you don't have to move at all while on the train, it does it all itself!"
If you have a spare ten minutes you can listen to the piece here (towards the bottom of the page). It's is nicely mixed with some chillout music and a poem from one of Mark's friends, about people's eyes meeting across a crowded Tube, or that James Blunt moment, as I like to call it.