The green/yellow earth wire has been recognized since the 1960s here as well, although only for the EGC in a cord.
The 1966 IEE Regs. specify only plain green, but the green/yellow was added as an amendment sometime later. The 1970 revised edition specifies green/yellow as being the only acceptable colors for a cord EGC, along with brown & blue in place of the old red & black for line & neutral respectively.
I've seen a few appliance cords made probably during late 1969/early-1970 period which actually have red & black along with a green/yellow ground. I'm not sure if these were British-made, or possibly Continental done for the U.K. market.
