A charity is calling on wildlife enthusiasts to help monitor signs of the UK's disappearing water voles.

People's Trust for Endangered Species (PTES) has launched the survey as part of its annual National Water Vole Monitoring Programme (NMVMP).

Over the last century water voles have experienced the most severe decline of any wild mammal in the UK as they face threats from invasive American mink, habitat loss and river pollution, PTES says.

In response to the dramatic decline PTES launched the NWVMP, appealing to members of the public to help look for signs and sightings of water voles.

The annual survey started again this month and runs until Friday, June 15.

Emily Thomas, key species monitoring and data officer at PTES, said: "Volunteers are crucial to helping us collect robust data about the state of our water voles across the UK. We use the data gathered to monitor population trends year on year, which in turn help guide our conservation efforts and inform us where action is needed most."

More than two hundred volunteers have taken part in the NWVMP since 2015, and last year volunteers collected data from 222 sites across England, Scotland and Wales, of which 82 had water vole signs present. PTES says there are gaps in survey areas where it needs more help, including the South West.

Volunteers are asked to survey one of 900 pre-selected sites across the UK, recording all sightings and signs of water voles along a 500m length of riverbank once during the course of the two-month period. No prior experience is required.