A friend (some years ago) managed to drill through a ring main cable in his kitchen. An electrician fitted a box and blanking cover and re-wired the section down to a socket that was fed by this damaged cable.
He would like to do away with the blanking plate as he wants to position a cupboard that will be half over where the blanking plate is and do some tiling.
I seem to recall that properly crimped connections are permitted - and that these can be buried in plaster (with a bit of protection).
Can someone point me to the authoritative information on this? He will be using an electrician - but wants to instruct the work correctly as one electrican has already wanted to re-wire back to another room and the disruption is not considered worthwhile.