The electrical installation industry isn’t is governed by law. This means anyone can do what they want and install electrics how they feel. 

Currently there is no legal requirement to comply with the requirements of BS 7671  

SIE (Safety In Electrics) are petitioning to make BS7671 Electrical Installation regulations a legal document and bring into line with gas regulations. This means all electrical installation works would need to be installed by registered qualified electrical companies only.