The Grass Snake is not only the longest in the UK, able to grow up to 150cm, but it can also swim underwater. BBC Countryfile said: "Grass snakes are generally found close to water and can swim ...

Britain's longest snake that can swim underwater The Grass Snake is not only the longest in the UK, able to grow up to 150cm, but it can also swim underwater.

There are three snake species native to the UK - adder, grass and smooth snake, but only one can swim. (Image: Getty Images) Snakes can be found all over the country in various habitats.