What 'breach' of Part P? As far as i'm aware that's just a building regulation that states the HOMEOWNER has to inform Building Control of electrical work. That's why people get away with doing it, because it's not an actual law governing what an ELECTRICIAN must and mustn't do.
That's because of how poorly Part P was introduced and awareness pushed out by the authorities.
It makes some work notifiable, but it also applies to ALL new work done that comes under building regulations.
In fact it's the only
legally binding document that covers electrical work, though it mostly just says 'do it as BS7671 says', with the exception of things like socket heights, etc.
It's only real clause is that:
"P1. Reasonable provision shall be made in the design and installation of electrical installations in order to protect persons operating, maintaining or altering the installations from fire or injury"
But breaching it is a criminal offence.
For whatever reason, the authorities almost never prosecute a breach of it though, and where electrical incompetence is involved they generally seem to go the EAWR route, perhaps because there are higher penalties (penalties for building regulations are fines only, though technically unlimited as to amount).
What SHOULD be happening is that LABC were funded and trained appropriately to monitor work in their area, and dish out enforcement notices to require crappy work to be corrected. Instead, building inspectors are generally being privatised, overworked, and as often as not barely visit a site any more in my experience, let alone monitor whether electrical work has been done properly. (Some areas are better than others)
Fun fact: The
current Part P document on the Gov.uk site still says: "Electrical installations should be designed and installed in accordance with BS 7671:2008 incorporating Amendment No 1:2011"