Unearthed after seven centuries the 'Black Death' pit skeletons that could unravel the medical mysteries of a pandemic

For seven centuries they have lain beneath the feet of commuters in one of the busiest parts of central London.

Thirteen skeletons, lying in two neat rows, 2.4m beneath a road in Farringdon, have been unearthed by excavations for London's Crossrail project.

The remains, which were found in a 5.5m-wide shaft at the edge of Charterhouse Square in Farringdon, are thought to be victims of The Black Death.

Builders working on the £15bn Crossrail project uncovered the bodies alongside pottery dating from the mid-14th Century.

Experts believe that the skeletons' arrangement in two neat rows suggests they date from the earlier period of the plague, before it became a pandemic and before bodies were thrown randomly into mass graves.

Scientists now hope that analysis of the skeletons could shed further light on the cause of the Black Death.

The skeletons were discovered in an area of London where experts believe many more bodies were buried.

John Stow, the 16th century historian, wrote in his 1598 Survey of London that 50,000 bodies were buried in what was then "no man's land".

Although that number is now widely believed to have been an exaggeration, the discovery of further remains has not been ruled out.

Nick Elsden from Museum of London Archaeology (MOLA) says that further discoveries are likely.

"The short answer is we don't know just how many skeletons are out there," he said.

Tests will be carried out on the skeletons but experts are linking the discovery with the Black Death as it is known that a burial ground for plague victims was opened in the Farringdon area.

A similar skeleton formation was found in a Black Death burial site in nearby east Smithfield in the 1980s. The skeletons are being carefully excavated and taken to MOLA for testing.

But Mr Elsden was quick to reassure the public that there was no longer any health risk from the plague which killed over a quarter of the British population in 1348.

"It's not something that stays in the soil. You have to actually meet someone who has it in order to catch it."

The bodies are not the first to have been uncovered by the Crossrail excavations.

Archaeologists have already uncovered more than 300 skeletons near Liverpool Street station.

Up to 4,000 skeletons dating from the 17th-19th centuries are expected to be found in the Bethlem "Bedlam" hospital burial ground, which is the site of of Liverpool Street's new stations.

At a Canary Wharf site builders also discovered 68,000-year-old mammoth bones.

The discovery of so many skeletons has led the Museum of London to admit that storage is becoming a problem.

Crossrail lead archaeologist Jay Carver said: "This is a highly significant discovery and at the moment we are left with many questions that we hope to answer.

"We will be undertaking scientific tests on the skeletons over the coming months to establish their cause of death, whether they were plague victims from the 14th century or later residents, how old they were and perhaps evidence of who they were.

"However, at this early stage... all points towards this being part of the 14th century emergency burial ground."

He added: "The general assumption about human exhumation is that they should stay in the ground. There is normally no justification for digging up skeletons except for important research like this, but we now have our sample."

Scientists are hoping to map the DNA signature of the plague bacteria and contribute to the discussion about how it may have led to the Black Death.

It is also hoped that the research could help combat modern day diseases.

"Many biologists are researching ancient diseases in the hope of better understanding the modern ones," said Mr Carver.

Around 75 million people globally, and up to 60% of the European population, perished during the Black Death which was one of the most devastating pandemics in human history.

It lasted between 1348 and 1350 and killed around 1.5 million Britons.