As of January 2005, there is an additional requirement to the Building Regulations, which is Part P Electrical Safety. The following leaflet is a summary of how High Peak Borough Council will apply the Regulations:
Building Regulations: New Regulation Part P Electrical Safety:
PDF version (27KB) 
You may find that other Local Authorities work slightly differently and you are advised, before undertaking any work, to check with the Council in whose area your project is.
A Building Notice application may be required for electrical works.
Alternatively there are many competent person schemes such as NAPIT, ELECSA, NICEIC to name a few. Electricians registered to one of the Part P schemes will register the works with the local authority and ensure that the building regulations are met.
See the Competent Persons leaflet (128KB) for further information.