Thank you, JP Knight of Nottingham, inventor of the traffic light, for making our roads – and now our operating theatres – safer.

After years of having to take their courage in both hands when crossing a busy road, MPs hurrying to vote were finally able to cross in safety when, on 9 December 1868, the first manually-operated traffic signals showing a red or green light at night were installed outside the Houses of Parliament in London. It would be another 60 years or so before they became a common sight though, with the advent of electric signals.

We've applied the same Traffic Light principle to our ECO-flow Stealth ultraclean ventilation (UCV) canopy.

Helpful perimeter LED lighting changes colour to indicate canopy status:

Green = UCV mode

Amber = Conventional mode

Red = UCV fault

Blue = HEPA filter dirty