Hunt for Anglo-Saxon abbey wall at Peterborough Cathedral Published duration 28 August 2015

image copyright Peterborough Museum and Art Gallery image caption In the late 10th Century, abbot Coenwulf built a wall around the precincts

Archaeologists surveying a cathedral's precincts are hoping to uncover the location of its walled Anglo-Saxon predecessor.

Peterborough Cathedral was built by the Normans after the 10th Century abbey burned to the ground in 1116.

Cathedral archaeologist Jackie Hall said the aim was to learn more about the Anglo-Saxon monastery because "we don't know enough about that".

It is more than 30 years since a dig discovered a small area of wall.

Dr Hall said: "They found the bottom of the wall, which was built out of bright yellow mortar and stone.

"We're trying to trace the wall through to another area."

image copyright Peterborough Cathedral image caption Ground penetrating radar is being used to survey the cathedral grounds

This survey is using a ground penetrating radar, which uses pulses to map the subsurface.

Dr Hall said: "The signal goes into the ground and reflects from all the layers that are below and bounces back."

She said it was "too early to say if we have found the wall" but remains "optimistic".

The Anglo-Saxon monastery was built on the remains of an 8th Century monastery destroyed by the Vikings.

image copyright Chris Downer/Geograph image caption The city was known as Burgh with St Peter which became Peterborough at some time after the mid-13th Century

The abbey became known as Burgh, meaning a walled town, and, after the dissolution of the monasteries, the Norman church became a cathedral serving the new diocese of Peterborough.

If the survey is successful, Dr Hall hopes the site will be excavated as part of a £2.5m Heritage Lottery funded redevelopment

She said this would help them understand "key question" of the relationship between the townspeople and the monastery.

"We don't even know if they lived within the walls of the burgh in the pre-Norman era - I'd love to know if they did," she said.