Stunning digital images have revealed some of the haunting medieval structures of a once-thriving north Suffolk community lost to the sea centuries ago.

Dunwich, near Southwold – dubbed Britain's Atlantis by heritage experts – slowly succumbed to coastal erosion that began in the 13th century and now little remains of the former capital of the region.

A team of experts has carried out extensive surveys of the seabed using special acoustic imaging equipment normally used to examine shipwrecks.

The results paint a fascinating picture of the long-lost community, which boasted eight churches and was at one time the largest and most important town in Eastern England.

The project has been led by University of Southampton professor David Sear and has produced the most accurate map to date of the town's streets, boundaries and major buildings, and has revealed newly discovered ruins on the seabed.

Prof Sear worked with a team of colleagues from the university's GeoData Institute, the National Oceanography Centre at Southampton, and Wessex Archaeology.

They were assisted by local divers from North Sea Recovery and Learn Scuba.

Mr Sear said: 'Visibility under the water at Dunwich is very poor due to the muddy water. This has limited the exploration of the site.

'We have now dived on the site using high-resolution Didson acoustic imaging to examine the ruins on the seabed – a first use of this technology for non-wreck marine archaeology.

'Didson technology is rather like shining a torch onto the seabed, only using sound instead of light. The data produced helps us to not only see the ruins, but also understand more about how they interact with the tidal currents and seabed.'

Peter Murphy, English Heritage's coastal survey expert, who is currently completing a national assessment of coastal heritage assets in England, said: 'The loss of most of the medieval town of Dunwich over the last few hundred years – one of the most important English ports in the Middle Ages – is part of a long process that is likely to result in more losses in the future.

'Everyone was surprised, though, by how much of the eroded town still survives under the sea and is identifiable.'

The project documented 10 buildings of medieval Dunwich, including the location and probable ruins of Blackfriars Friary, St Peter's, All Saints and St Nicholas churches, and the Chapel of St Katherine.

Additional ruins were also discovered which seem to be part of a large house, possibly the town hall

Mr Sear added: 'It is a sobering example of the relentless force of nature on our island coastline. It starkly demonstrates how rapidly the coast can change, even when protected by its inhabitants.

'Our coastlines have always been changing, and communities have struggled to live with this change.

'Dunwich reminds us that it is not only the big storms and their frequency – coming one after another – that drives erosion and flooding, but also the social and economic decisions communities make at the coast.

'In the end, with the harbour silting up, the town partly destroyed, and falling market incomes, many people simply gave up on Dunwich.'