LONDON'S oldest timber structure has been unearthed during an excavation of a prehistoric peat bog.

Archaeologists were digging alongside Belmarsh Prison in Plumstead ahead of construction work on a new building when they discovered a timber trackway thought to be nearly 500 years older than Stonehenge.

The team, from the Institute of Archaeology at University College London, made the discovery when digging 4.7m below the surface - around the height of a double decker bus.

They took samples to a lab where radio-carbon dating showed the structure was nearly 6,000 years old making it nearly half a millennium older than Stonehenge.

Diccon Hart, the archaeologist who lead the excavation, says the wetlands next to the Thames were an important source of food in prehistoric times and that trackways made it easier for people to cross the terrains.

His team also found a piece of log with unusually well-preserved tool marks made by a metal axe.

News Shopper: A piece of timber was found with marks from a metal axe

He said: "The discovery of the earliest timber structure yet found in the London Basin is an incredibly exciting find.

"It is testament to the hard work and determination of those who toiled under very difficult conditions to unearth a rare and fascinating structure almost 6,000 years after it was constructed."

Archaeological advisor at English Heritage, Mark Stevenson, says it is a very important discovery.

He said: "The timber structure is slightly earlier in date than the earliest trackways excavated in the Somerset Levels, including the famous 'Sweet Track' to Glastonbury.

"This large area of development has been the subject of extensive building recording of the old Royal Arsenal East site as well as detailed work to map the buried ancient landscape."

The oldest timber structure in London before this find was a timber trackway in Silvertown, which has been dated to 3340-2910 BC - 700 years younger than the new find.