Mike Lavelle discovered a cache of grass snake eggs in his compost heap a few weeks ago and they have just hatched. He reckons that there were about 20 eggs (the white leathery things on the right of the photo above). The mother lays the eggs and then leaves them to it. The gestation period is 10-20 weeks. The heat of the compost decomposing incubates the eggs nicely and the hot weather has definitely helped. The young snakes are still there and getting bigger. There is a very brief 3 second video below (set to loop).
A key identification feature is that yellow collar encircling the back of the head. For those of you that get the Parish Magazine, in the September edition there is an interesting article by Michael Blencowe of the Sussex Wildlife Trust about grass snakes.