The Day of the Triffids!!!

I walked down our driveway last week as normal on my way to the local shops. It was a lovely warm evening and everything seemed fine. However, something rather strange had happened while I was gone. I walked back home to find this massive plant on the side of our house had just fallen down and completely blocked the drive. My partner had watched the plant slowly fall to the ground while he was working on his car. I'm pleased it happened on such a nice day!! The plant had been climbing the side of the house for many years.. I wonder what caused it to fall when it did?.....