You’ve probably seen these dotted around a few places, what looks like some sort of security barrier, but wondered how such an odd thing could work. Does something rise up from under the plate, are the walls active in someway, just what does it do?

In fact, the function is pretty much the same as bollards that are fixed into the ground, to stop a road impact, just without the hassle of digging deep holes in the ground or ripping up the pavement.

Bollards, once basically a heavy metal tube and not much else have, of necessity become rather cleverer in recent years. The range in rating from simple impact barriers for light vehicles where a bollard is simply inserted into the ground, to large underground structures where the bollard is just the tip of the proverbial iceberg.

These bollards which I have in a number of places, such as outside St Paul’s Cathedral, and here at Victoria station act in a different way.

Designed by ATG Access, the Surface Guard are temporary barriers that can be placed around events or buildings, and were first developed in 2017.

Those crumpled weak looking plastic barriers are just a cladding, and what’s underneath is enough to give people second thoughts about ramming a vehicle at them — massive spikes.

The design takes advantage of a number of factors — the long strip ensures when an impact hits, the whole barrier has to be moved, which adds weight. Also the wide plate should mean that the vehicle is impaled on the spikes, and it’s motor wheels are embedded within the structure rendering them impotent at moving the barrier forward.

The system recently passed impact tests, where it prevented a 7,200kg lorry travelling at 32kph from penetrating less than five metres.

These are not the only barriers with spikes — the basic looking steel bollards you see in places often conceal a heavy duty steel structure inside, with a lot of teeth to grip and hold anything that rams at them.

The big plant pots outside offices aren’t filled with concrete, but a fine honeycomb of aluminum that’s designed to crumple and absorb the impact energy.

However, these odd looking grey plastic barriers do have the advantage of being more permeable for the public and less of an, ahem, barrier.