Archaeologists have described the discovery of a 2,000-year-old anchor on the seabed off Suffolk as an "incredibly rare" underwater find.

The distinctive wrought iron anchor was found 140 feet down in the southern North Sea during survey works for ScottishPower Renewables’ £2.5billion East Anglia ONE offshore windfarm.

Experts believe the anchor is a rare example from the Roman or possibly late Iron Age – somewhere between 1,600-2,000 years old – and is evidence of Romans' seafaring and trading off the coast of the East of England.

Brandon Mason from Maritime Archaeology Ltd said: “Everything points to this being a Roman anchor of almost 2,000 years old, which is an incredibly rare piece of history.

"If this date is confirmed, it would be hard to overstate its significance – we only know about three pre-Viking anchors from northern European waters outside the Mediterranean region and only two actually survived.

“We believe this find could be the oldest and one of the largest surviving examples, giving us hard evidence of the incredible amount of activity that must have been going on in the waters in Roman times, but that we know relatively little about.

"It’s an absolute privilege to bring the anchor to the surface and to share its story with people not just across the East of England, but right around the world."

More than two metres long and weighing around 100kg, the anchor is estimated to have come from a 500-600 tonnes vessel, possibly one of the larger merchant ships of the Roman fleet.

While analytical work is ongoing to confirm the date, there are several features that suggest the anchor could come from the Imperial Roman period.

The anchor was first discovered in 2018 during marine seabed survey works by ScottishPower Renewables for its East Anglia ONE offshore windfarm around 40km off the Suffolk coast.

The completed windfarm has 102 turbines with the capacity to produce 714MW of green electricity – enough to power the equivalent of more than 630,000 homes.

Protected by an exclusion zone installed on the seabed during construction works and monitored using remote underwater technology due to concerns over its long-term preservation, the anchor was safely and carefully recovered from the water in 2021.

It is currently undergoing detailed imaging and analysis to better pinpoint its age and eventually will go on permanent display in conjunction with Colchester + Ipswich Museums.

The conservation works are being carried out by ScottishPower Renewables’ commissioned specialists Maritime Archaeology Ltd, in conjunction with the Mary Rose Archaeological Services, and with advice and guidance throughout the process from Historic England’s material science experts.

The anchor is the latest in a series of important historical and archaeological finds during the work on the windfarm.

These include a missing German submarine from the First World War, numerous artefacts from the Bronze Age, Iron Age, Roman and Medieval periods discovered during onshore excavation works, and a prehistoric monument – dating back more than 4,000 years – complete with a rare Neolithic wooden trackway and platform and an ancient wild cattle (Auroch) skull radiocarbon-dating to around over 6,000 years old.

Ross Ovens, ScottishPower Renewables’ managing director – East Anglia Hub, said: “Our East Anglia ONE windfarm has proven to be an archaeological treasure trove – both onshore and offshore –  and this latest find shows that it just keeps giving.

“As part of the Iberdrola Group, we pride ourselves on the sensitive way in which we approach our offshore projects across the world to ensure that their environment and heritage are protected and preserved and it’s fascinating to see what that means in practice. The East Anglia ONE finds will tell us so much not just about East Anglia’s history itself, but also the region’s place in British history."

Stuart Churchley, Historic England marine planning archaeological officer, praised the careful and methodical steps taken to preserve the anchor and map and investigate the sea floor.

He said: “For the anchor, the resulting analysis and conservation is an important next stage. For this reason, ScottishPower Renewables is commissioning a process of analysis to explore the material form of the anchor. Historic England’s material science experts have been providing guidance on this element of work, with some of the techniques not used before. It will be great to see the plans for it to be exhibited locally come to fruition.”

The anchor will be available for visitors to Ipswich Museum to see on Tuesday, September 27, before it is taken away for key conservation work ahead of returning permanently in 2025.