According to the patent, the intensity could be increased from causing discomfort to the point where targets become “temporarily incapacitated”. In the rather formal language of the testing company the riot shield uses a folded acoustic horn which is incorporated into the physical shell of the shield that can be directed at certain targets inducing both pain and physical impairment. In real terms it looks like a normal riot shield with a massive speaker tied to the front with wires.

A research expert in police ethics warned that the biggest danger is that the technology would be used for political control. “If authorities in Egypt or Syria had this, would they use it for dispersal or to shove crowds into potentially lethal harm’s way?” he asked from Leeds.

Given the new police commissioners penchant for expensive novelty devices – it was Bernard ‘Hulk’ Hogan Howe the Oxbridge graduate now in charge of the police who introduced the enormous ‘Berlin wall’ style crowd barriers onto the streets during the last student demonstration and his dedication to kettling – it won’t be long before we see the British police using the new riot shields for political purposes.