Massive grass snake
I was sitting on the terrace reading about 3 ish when I saw something move out of the corner of my eye; it was a snake about 1m long. I did a vertical takeoff, like a Harrier Jump Jet from shear surprise. I'm actually rather fond of snakes and once did a days work with a python wrapped round my neck I checked online and it was a grass snake, not an adder. It was very beautiful; it raised it's head to me and then slithered off into the flower bed.