An ancient Roman sarcophagus has been excavated from a building site in London.

The 1,600-year-old coffin, which was discovered near Borough Market in central London, is thought to contain the remains of a mother after the bones of a baby were found nearby, experts said.

Archaeologists lifted the lid of the stone coffin on Tuesday and found small bones and a broken Roman bracelet in the surrounding soil.

Archaeologists prepare to lift the lid at the site in Swan Street, Southwark (Lauren Hurley/PA)Archaeologists prepare to lift the lid at the site in Swan Street, Southwark (Lauren Hurley/PA)

The team behind the discovery are not certain the infant was buried with the coffin, however, as it appears to have been opened by grave robbers in an area that was used by the Romans as a burial ground.

Gillian King, senior planner for archaeology at Southwark council, said a large crack on the lid was probably the work of thieves.

“It’s been broken into two pieces, probably when robbers broke into it during the post-medieval period,” she said.

“We hope that they will have left the things that were of small value to them but great value to us as archaeologists.

Archaeologists discovered the coffin six months into the dig (Lauren Hurley/PA)Archaeologists discovered the coffin six months into the dig (Lauren Hurley/PA)

“We always knew this site had the potential for a Roman cemetery, but we never knew there would be a sarcophagus.”

The coffin was found on Swan Street last month after the council told developers to pay for an archaeological dig on the site.

It was found several metres underground with its lid slid open, and experts suspect it was targeted by thieves back in the 18th century.

The council had asked developers to check the area for ancient finds before it went ahead with building new flats because of the site’s proximity to two large Roman roads.

The sarcophagus will be taken to the Museum of London's archive (Lauren Hurley/PA)The sarcophagus will be taken to the Museum of London’s archive (Lauren Hurley/PA)

Strict rules on Roman burials, which had to be outside of town walls, meant the location was a prime spot for historical finds.

Archaeologists discovered the coffin six months into the dig as they were due to finish their search.

They believe it was the coffin of a high status inhabitant of Roman London, but they will not know for sure until the bones and soil inside are tested and dated.

The sarcophagus will now be taken to the Museum of London’s archive in Hackney for analysis.