Dig, dig keep digging.... oops, bit much there lads.. Oops the house has fallen down.

Some thing like that

Short version.

Greedy developer buys house in need of repair for ?900k, gets greedy and against planning permission decides to build a basement flat. Digs out the entire foundations, poorly underpinning it.
Neighbour stops me one afternoon and says.... "look"

I call 999, police arrive and close the road, evacuated us for just under a week.
House continues into its own foundations. 120 tones of concrete pumped into the basement, and structural scaffolding put up to make safe.

5 months later, the demolition has started.