What is the biggest Reptile in the uk?

The biggest reptile in the UK is the European adder (Vipera berus), which can grow up to about 90 cm (35 inches) in length. However, in terms of sheer size, the common slowworm (Anguis fragilis), a legless lizard often mistaken for a snake, can also be considered one of the larger reptiles, reaching lengths of up to 50 cm (20 inches). Both species are non-venomous and play important roles in the UK’s ecosystems.