Which reg specifically - other than general "good workmanship" ?A bad install and against reg's
And if it's a radial circuit ? The "all the sockets on the wall don't work" suggests that it's not a ring. It may be a radial, or it may be a non-compliant install, or ... Not enough information to be definitive about it.the maximum amount of cables you should ever have on a socket is 3 per terminal.
ring in
ring out
+ 1 spur at the most.