In my previous house the owner had installed a 2 kw heater in the
conservatory. As there was not socket he had dropped a feed down from
the lighting circuit. I only found out when I plugged in my rcd in
order to use the lawn mower and it kept tripping. This was because the
lighting circuit had no earth. I am assuming he didn't use the heater
very often, or maybe he just put in a larger fuse!

He also built a retaining wall, 6 feet high from a single skin of
bricks, not tied in to anything and with no drain holes. Unsurprisingly
this had started cracking and bowing and I was able to knock it down
with a kick.

He also built an arch of single bricks by the side entrance. This was
not tied into the house wall, but was just sort of wedged against it.
It had cracked and I thought it unsafe, so when investigating it gave
it a little rocking and it fell down onto the path below causing a
massive crack in the concrete.

There were numerous other bodges, but these were the 3 most serious,
all of which could easily have led to death or serious injury.

So although new building regulations (such as Part P) are annoying, I
can see the point. Not sure whether they will deter people like this
though.