It's not often something stops you in your bike tracks. But a spectacular "bike tree" invention from Japan bowled me over when I was in Tokyo a couple of weeks ago.

Fed up with bicycles locked to railings, piled on top of each other, blocking doorways and roads, a local council in the city installed the mechanical masterpiece. It's basically an automatic storage system for cycles and operates with computer tagging of bikes and either storage in a building or a basement structure.

There are a number of locations where these bike trees are now in place in Tokyo – some hold 600-odd bikes, others more than 6,000. The concept came from the massive Japanese steel company JFE, whose engineering works division first started them in 2007 but are now spreading.