Get Some F**king Lights

reading the wiki page I linked it mentions amber lights...

Amber yellow lights

Amber lights grant no priority in traffic and exist purely to advertise the vehicle's presence. The Regulations specifies several classes of vehicles which may use amber lights, such as towing, highway maintenance, pilot vehicles escorting an oversize load, and vehicles unable to travel over 25 mph[30] and fitting these lights to other vehicles is technically illegal (although these beacons are widely fitted to vehicles as wide ranging as security and ambulances).

if this is the case why don't bicycles use amber lights to warn of their presence? I'd have thought this was the colour if any that should be used...