Why?

A few years ago we saw this house on the news - we were still living in Surrey - apparently the owners had literally demolished the house overnight, the people in the house it had been attached to had something of a shock when they saw what had happened! Some new hoardings have been erected around the site, but other than that, this is how it has looked for years now.
It's Sunday - we're in Newcastle! And it was sunny - but blustery.