Re: Blue bulb legal?
OK, the situation with proper blue lights (not the so called blue headlamp bulbs) is this:
Part II of the Road Vehicles Lighting Regulations states...
Colour of light shown by lamps and reflectors
11.—(1) No vehicle shall be fitted with a lamp which is capable of showing a red light to the front, except-
(a) a red and white chequered domed lamp, or a red and white segmented mast-mounted warning beacon, fitted to a fire service control vehicle and intended for use at the scene of an emergency;
(2) No vehicle shall be fitted with a lamp which is capable of showing any light to the rear, other than a red light, except-
(h) blue light and white light from a chequered domed lamp fitted to a police control vehicle and intended for use at the scene of an emergency;
(k) blue light from a warning beacon or rear special warning lamp fitted to an emergency vehicle, or from any device fitted to a vehicle used for police purposes;
Restrictions on fitting blue warning beacons, special warning lamps and similar devices
16. No vehicle, other than an emergency vehicle, shall be fitted with-
(a) a blue warning beacon or special warning lamp, or
(b) a device which resembles a blue warning beacon or a special warning lamp, whether the same is in working order or not.
So it appears that blue lights can be fitted to vehicles provided they do not emit blue light to the rear, flash or resemble a warning beacon.
However in this case it is illegal because the bulbs are fitted in a Turn Signal lamp and that contravenes the colour requirements of the turn signal, i.e. colour emitted by a turn signal must be amber.