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An exceedingly rare joy, this one. Recorded in 1979 in an almost bankrupt New York, when Manhattan – imagine! – could still be a dangerous place and riding the subway was strictly for the brave, this is a touching and profoundly funky tribute to the vigilante volunteer security force, before things went a little stale for them. (There is a London chapter, but only a handful of members remain.)

With bass as heavy as rolling stock, and field recordings from the subway tannoy echoing along almost empty train carriages late at night, Margo Williams's vocals supply the inner city funk menace with some almost ethereal soul. It's produced by Patrick Adams and Peter Brown, the same team who brought us InDeep's Last Night a DJ Saved My Life.

I was introduced to this by a Disco Juice compilation, but I still don't really understand it being filed under this heading: it's soul, and it's funk, with the early stirrings of hip-hop murmuring in the background. (En passim, wouldn't it be great to see the revival of the term "disco" for clubs? They could maybe call them compact discos these days. I feel certain it would have a positive effect on the music.)

The video is a very short edit, which I've included because of the pictures, but you can hear the full version here. Often find myself humming this as I arrive at this Guardian's offices, where we watch night and day for injustice and care deeply for you, if only you'd notice and buy more papers.