I must admit I'm being slightly mischievous, but there is an important point at stake, and people should think about what they are doing, and why.ebee said:He means to comply with BS 7671 which he needs not but nevertheless might be a good idea if folk did comply.
1) Compliance with BS 7671 is not legally mandatory.
2) Compliance with the Building Regulations is mandatory.
3) BS 7671 EICs permit exceptions to be documented.
4) Mandatory requirement P1 in the Building Regulations says "Reasonable provision shall be made in the design, installation, inspection and testing of electrical installations in order to protect persons from fire or injury." I believe that it is perfectly reasonable to regard the continued use of old colours to maintain and extend existing installations as safer than arbitrarily introducing new colours.
I wonder when the first recorded case will be of a cowboy trying to dupe some poor householder into having a rewire because the colours have changed, see, and you have to use the new ones now...