added to this thread on suggestion
british reptiles:
Adders
These are found all over Britain and are our only snakes with a poisonous bite, but this is rarely fatal to humans. Adult adders are usually up to 66 cms long. Background colouration is a light shade of grey or brown with a black zigzag marking along the length of the back. As with all reptiles, colouration varies and becomes duller as sloughing (skin shedding) approaches. Adders have the most varied diet of British snakes, feeding mainly on field voles, but also mice, lizards, nestling birds, eggs and amphibians.
Grass snake
Grass snakes, which are usually around 120 cms long, live in a variety of rough habitats with long grass, and lay their eggs into piles of warm, rotting vegetation. They become rarer the further north you travel and are hardly ever found in Scotland. The background colour is dark green and the body is marked with black vertical bars and spots which run along the sides, and there is usually a collar marking.
Grass snakes are surprisingly good swimmers and they feed mainly on amphibians such as toads, frogs, newts and small fish.
Smooth snake
The smooth snake (length up to 70 cms) lives on heathlands in Dorset, Hampshire and Surrey where it can lay its eggs in sandy soils. These snakes have round pupils to their eyes, greyish background colour with usually two rows of darker brown or black markings along the back. Smooth snakes feed on other reptiles, mostly slow worms and lizards, but small mammals such as pygmy shrews and young birds are also taken.
Sand lizard
The sand lizard prefers to lay eggs into shallow hollows dug in sandy soil. Like the smooth snake, it is found mainly in southern Britain, but also on the dunes of the Merseyside coast. These lizards, which can grow to 20 cms, have a grey-beige background with dark brown blotches. Sand lizards have the ability to take food in large quantities when it is freely available and will eat most types of insects, worms, slugs, and can eat their own young too, if necessary.
Common lizard
Common lizards (also known as viviparous lizard) can live almost anywhere, but they prefer reasonably warm places with good basking sites and are frequently found on the stony ballast around railway lines. Adults can reach 14 cms and colouration can include shades of brown, grey and dark green. They are insect eaters and also eat small snails.
Slow worm
Slow worms are really lizards, but have evolved into a legless form to suit their burrowing lifestyle. Slow worms prefer well vegetated places which give good cover from predators. They have an almost cylindrical body which is hard and smooth to the touch, with a polished-looking grey or brown colouration. The young are shades of coppery gold with vivid dark brown sides. They feed mainly upon slugs, but also eat worms, spiders and snails.
I have personally seen all of these with the exception of sand lizards. I will be taking a trip to salisbury later this year in the hope of spotting at least 1.