I've had so many other questions about U.K. wiring that I haven't gotten to the question of color codes. So.....

The original British color ("colour" if you want to be REALLY British!) code is:

hot=red, neutral=black, earth=green.

Unfortunately, it's a little more complex than that, because in 1970 we adopted a common European system for the flexible cords on appliances:

hot=brown, neutral=blue,
earth=green/yellow stripes

Fixed wiring cables cotinued with the old colors, although the plain green for ground has now given way to green/yellow.

For fixed 3-ph. wiring the phases are red, yellow, and blue, or for wiring installed prior to 1965, red, white and blue.

Pauluk, the color code you described is used on all of the proximity sensors and photoelectric sensors I install here in an industrial setting. The box says it is an IEEC standard. Sure had this American guy scratching his head for a while. It's not normal!!

In the early '70's I worked under a fellow that was from Australia. He loaned me his correspondence course paperwork from the "Royal Melbourne Technical College" to help me learn 3Ø theory.(star rather than wye)
We installed everything in our factory with the Red, Yellow, Blue colo(u)r code, although we were in Anaheim,CA. Did use white as our neutral though.
I've become accustomed to seeing the brown/blue etc., on machinery & the like but it certainly throws some of the younger guys off!
Do you use much 3Ø power in the UK? What's it's voltage?

Yes, the brown/blue code is an IEC standard and those colors are used throughout Europe now, and for flexible cords in Australia, New Zealand, and a lot of Africa. As the marketplace becomes more global, I guess you'll be seeing more of it.

When the new colors were introduced here it caused a certain amount of controversy. After all, we now have blue in a flexible cord which is neutral, but blue in a fixed cable is phase!

Another problem is the green/yellow ground colors. Originally, the colors were about 50/50, but the sleeving used on bare ground wires now is mostly yellow with just a thin longitudinal green stripe. If it's turned the wrong way at the back of a box, it can look like a plain yellow phase wire.

Australia uses different plugs and circuit arrangements than here (no rings), but they inherited a lot of British technical standards, including color codes, distribution voltages, etc.

Yes, 3-ph. is very common here. In fact most distribution is 3-phase, standardized in the early 1970s at 240/415V. Normal residential service is just 2-wire 240V tapped off one phase and neutral.

About the only place to see a single-phase xfmr is feeding 240V 2-wire to a remote home or farmhouse.