What lies hidden in Canary Wharf's steel plant pots (2013)

If you travel around Canary Wharf, or some parts of the City of London, you cannot fail to notice large steel plant pots that have sprung up around buildings.

Sadly, not simply decorative — they are in fact the apparatus of security, designed to protect the buildings from attack by bomb laden vans that terrorists may choose to try and drive into the entrances.

You might suspect that these are just very large boxes – maybe filled with concrete or soil for the plants, and that is about all there is to them. However, the other day I got to see the contents of a naked box, and there is some quite interesting design concealed within their steel claddings.

The contents aren’t secret — but not something people probably think that much about — and I am always curious about things we normally pass by with barely a second glance.

Designed by Willerby Landscapes, these metallic boxes are actually capable of stopping a 7.5 tonne lorry traveling at speeds of up to 65km/h — which is actually damn impressive for a “metal box” that is just sitting on the pavement. Nope, they aren’t bolted to the ground.

What is described as a “patented internal impact absorbent core” is actually an initially obvious set of V shaped struts.

More interestingly, some of them are filled with a honey-comb style filler which would crumple down when hit – and the more surface area you have, the more energy can be absorbed by the planter as the honeycomb structure crumples to slow down the attacking vehicle.

Although the containers look the same on all sides, according to the patent, they in fact have a front and a back, and one side is designed to face outwards, and crumble when hit to absorb the energy of the impact.

So, when you next have to navigate around these metal containers cluttering up the pavements of Canary Wharf, give a moments thought to the thinking that has gone into their construction.