The discovery was made as workers dug up a concrete courtyard floor, revealing the capped structure beneath. Paul Kirkby of the Caistor and District Trust said the well was originally constructed during the Roman occupation and later adapted in the 18th century.

Georgian wall panels and timberwork were also found during the restoration.

“We found cappings over what is clearly a Roman well that had been modified at a later date with Georgian brickwork,” Mr Kirkby said.

Although the well has been re-capped for now, the trust hopes to restore it in future. They are seeking £25,000 in additional funding on top of the £4.4 million already committed to the wider renovation project.

Caistor, whose name derives from the Latin castra meaning “camp”, was once a Roman stronghold. The building is being transformed into a heritage hub featuring retail units, meeting rooms and holiday accommodation.

Work is expected to finish in the summer.