Who's to say why there's a tank by the side of the road?

I went for a walk through South East London yesterday and came across this tank on the corner of Mandela Road and Page's Walk (I think!)
A man who works locally stopped and said he'd been driving past it for years but had never stopped to look at it before. We ended up talking about how we both wanted to know more. Why wasn't there a blue plaque? he said. Why wasn't there an explanation?
I've been thinking about this since and I can't decide whether I respond positively to this need for stories, for explanations, for narratives about unexplained things, or whether I find it a bit depressing that our immediate response is to look elsewhere for an explanation - that we want someone else to author our city and our experiences for us, rather than delighting in the opportunity to make up our own stories.
Maybe I'll write a spoof blue plaque...