This video is called Britain in COLD BLOOD – The Grass Snake (Natrix natrix).
Translated from Knack weekly in Belgium, 7 July 2014:
The grass snake is on the rise in Flanders. The snake which until recently did not live in Flanders has been observed 27 times since the beginning of this year. VRT TV reports this.
The grass snake hibernates and lays its eggs inter alia in compost heaps. Probably the animal was brought from Germany with compost and the snake came to Limburg province that way.