The National Trust is asking beach-goers to post pictures on Instagram to help monitor coastal erosion.

A photo stand has been erected at Studland Bay in Dorset, inviting passersby to stick their smartphones into a slot and snap photos.

The sign then asks them to post the images on social media using the hashtag #NTshiftingshores.

There is just one rule: no zooming or filters.

They will then be swept up from social media by the charity and made into a timelapse film showing how the shoreline has changed over time.

The National Trust, which manages more than 780 miles of coastlines across Britain, aims to use the data to help plan ahead to protect wildlife, flora, fauna and buildings.

Hundreds of people have already posted pictures online, showering praise on the charity for its innovative idea and calling for it to be rolled out across all beaches.

One Twitter user captioned their coastal photo: "For anyone who thought the Instagram generation needed to take a break from #social on their days out, why not embrace it and use it to your advantage?! #ntshiftingshores".

Another wrote: "Doing my bit for the National Trust project at Studland Bay #ntshiftingshores".

More than 400 people have published their photos on Instagram, with tourists from America and Thailand among those joining in. Pictures date back as far as June 2016.