Grass snake

The grass snake ("Natrix") is a non-venomous snake. It is often found near water and feeds almost exclusively on amphibia and lizards.
The grass snake is widely distributed in mainland Europe, from mid Scandinavia to southern Italy. It is also found in Middle East and northwestern Africa. 
There is a native species in Great Britain but it is not "Natrix natrix". It is "Natrix helvetica" the barred grass snake. The two subspecies were both called "Natrix natrix" until recently (2017).
Work by the Senckenberg Research Institute in Germany lead a study into the genetics of over 1,600 grass snakes.