We’ve all been there, the traffic light turns from green to yellow and you’ve got a split second to decide whether to hit the brakes hard or step on it and blast through before it's red.

Then something happened which Nadim could never have imagined: “Just as it couldn’t get worse, these five angels just appeared, and this yellow light, strong, soft yellow light, rather like a ...

The team did tests on mice, fixing the brightness to high or low and switching the colour from blue to yellow. Bright light of either colour was stimulating, rather than restful, as expected.