The dig is gradually revealing substantial remains of long-lost structures that once surrounded the 14th-century Tower of Drum.

The excavations are part of the ongoing National Trust conservation project which saw the tower reopened to the public last month after a year behind scaffolding.

A trench in the castle courtyard is concentrating on exploring Drum’s historical sanitary arrangements.

The Trust’s Archaeologist for Eastern Scotland, Dr Shannon Fraser, said: “This project is giving us a great opportunity to fit some of Drum’s historical jigsaw pieces together again, giving us a better understanding of the different ways in which people lived in the castle over the centuries.”

So far a large, stone-lined cesspit has been found, which would have taken the waste from two garderobes, or toilets, within the tower, as well as receiving waste from an outdoor toilet.

Animal bones and shards of medieval pottery have been found in the upper levels of the pit. Archaeologists are hoping that waterlogged items such as grains, seeds and fish bones may be preserved in the lower levels of the cesspit, which would give an insight into what people in the castle had been eating.