What is the rarest type of shrew in Britain?

The rarest type of shrew in Britain is the water shrew (Neomys fodiens). Although not critically endangered, it is considered rare due to its specific habitat requirements and declining populations in some areas. The water shrew is distinguished by its aquatic lifestyle and larger size compared to other shrew species, and it primarily inhabits wetland areas, streams, and rivers. Conservation efforts are important to protect its habitats and ensure its survival.