The remains of a Roman fort have been unexpectedly discovered under Exeter Bus Station.

Archaeologists have described the find, which occurred during redevelopment of the site in the Devon city, as “very important”.

A Roman ditch was first uncovered, with further excavations revealing two further ditches running parallel to each other.

These belong to a new and previously unknown Roman military site, which was either a fort occupied by a military unit, or a defended compound.

Coins and local pottery made in the area for the military, as well as fine red Samian tableware imported from France, were also discovered.

Roman fort discovered under Exeter bus station
Detail of the remains of a Roman fort (Exeter County Council/PA)

The find was made by the Exeter office of Cotswold Archaeology, who are working with Kier Construction ahead of the construction of a new bus station and leisure complex.

Andrew Pye, archaeology officer at Exeter City Council, said: “This is a very important, and completely unexpected, discovery, in an area that has been heavily changed by previous post war redevelopment.

“Along with other recent work in Exeter, it demonstrates just how much of the city’s history can still survive in unlikely places, despite damage caused by bombing and modern concrete foundations.

Roman fort discovered under Exeter bus station
Workers carry out excavations (Exeter City Council/PA)

“As the city continues to grow and renew, it is a good example of how the planning system and developers work together to make sure that remains that are inevitably affected by new development are properly excavated and recorded for the benefit of this and future generations.

“This discovery of yet another new Roman ‘fort’ within the city does demonstrate, along with that of the fortress and baths back in the 1970s and of several other new major military sites in the last decade, just how pivotal a role the Exeter area played in the first decades of the Roman conquest and subjugation of Britain, and how crucial development led archaeology has been in revealing this.”

The council said that archaeology work at the site, between Bampfylde Street and Cheeke Street, would not affect the construction timetable.

Roman fort discovered under Exeter bus station
A fragment of pottery (Exeter City Council/PA)

A Roman fortress was established in Exeter in around AD55, with a civilian town later established there as the regional capital of south west England.

The fortress and its bathhouse was discovered under the Cathedral Green in the 1970s and more recent work has uncovered other finds in the city.

These include large buildings, forts and military depots.

Derek Evans, of Cotswold Archaeology’s Exeter office, said: “The unexpected nature of this discovery and the significance of uncovering previously-undocumented Roman military features in this area of the city, have made this a challenging and interesting project.

Roman fort discovered under Exeter bus station
A worker holds another artefact (Exeter City Council/PA)

“We look forward to undertaking further analysis of the finds and other material recovered during our works and refining the story of the site’s history.”

The present bus station was constructed in the early 1960s and any remains present at that time would have been destroyed over most of the site.

At that time, there was no planning requirement for developers to record remains.