Adders are to be given protected habitats by roadsides in an attempt to boost numbers as conservationists insist they pose "little risk" to the public.

Denbighshire County Council is believed to be the first local authority in the UK to unveil plans to use roadside nature reserves to help preserve Britain's only venomous snake.

The measures come amid fears adders are vanishing across Britain with the species believed to be extinct in Nottinghamshire and Warwickshire. They are also considered to be endangered in Oxfordshire, Buckinghamshire, Hertfordshire and London.

Experts say a loss of natural habitat and human "persecution" has damaged adder population numbers.

In North Wales, seen as one of the reptile's last remaining strongholds in the UK, work has started to create a designated 150m stretch of roadside verge in Hiraethog, which the council aims to monitor and protect the snakes under a "specific habitat management plan".