To the so-called electrician who originally installed the electrickery sockets in my kitchen...
Fuck knows how you got your qualifications (assuming you had any), given what I found when I rashly decided to re-position the electric socket on the north wall of my kitchen today. I knew something was amiss when I started undoing the screws that secured the back box to the wall, and felt something move.
That something was the joist off-cut that you had used to not quite fill the gap between the rear of the back box and the inner face of the cavity wall outer leaf. Ordinarily, there should be brick or breeze block between the back box and the cavity, but it looks like you fucked up quite badly when chasing out the hole, and you broke right through when you spalled a great big lump off the cavity-facing side of the inner leaf. You could have at least tried to make an effort when bodging a repair, and actually mortared the wood in place.
It's a good thing I happened to have a couple of spare bricks in the shed, and some rapid-set mortar left over from another DIY task, so that I could carry out the proper repair that you should done in the first place, you fucking moron.