Ancient timbers uncovered as part of engineering work and mistaken for modern fence-posts could belong to a 4,000-year-old walkway across marshland on the Norfolk-Suffolk border, archaeologists revealed last night.

Ancient timbers uncovered as part of engineering work and mistaken for modern fence-posts could belong to a 4,000-year-old walkway across marshland on the Norfolk-Suffolk border, archaeologists revealed last night.

The archaeological find, the first of its kind in the region, has been made on the banks of the River Waveney during flood defence work.

Iron Age timbers have been preserved "extraordinarily well" according to archaeologists working at the site, on the Suffolk side of the river, near Beccles.

Now the contractor, Broadland Environmental Services Limited (BESL), has roped off the area and paid for a three-week dig to take place at the site to see what else can be found out about the wooden structure.

Jane Sidell, English Heritage archaeological science advisor called the discovery a "nationally important find".

"This is the first such structure to have been discovered within Suffolk and is one of only a few in Britain," she said.

"And as such is a nationally- important find. It gives us an excellent opportunity to examine ancient, possibly ritual, use of the marshland, and how the marshes have developed over time."

William Fletcher, from Suffolk County Council's archaeological service, said the find was "something we are very excited about".

"We don't really know what the timbers would have been for, but one possibility is that they could have been used as some kind of boundary marker. They are 3,000 to 4,000 years old.

"Another possibility is that it was a walkway or causeway used to get people out across the marshes.

"Before the area was drained, it would have been very marshy and this could have been a way of getting out over the marshes to the river."

The land where the timbers were discovered is owned by Beccles Town Council, and it is hoped that a display might be set up in the town once the dig is complete to show local people what has been found out about the site.

As the ground has been disturbed, it was feared that the remaining timbers within the site would start to decompose.

Following advice from English Heritage and the county council, BESL has commissioned a full-scale archaeological excavation to record the remains and learn more about the structure. Where the ground has not been disturbed the site will be left intact and preserved for future generations.

A team of archaeologists from the county council and the Institute of Archaeology and Antiquity at the University of Birmingham will carry out work to fully assess the significance of the remains and the context of the site.

Jack Walmsley, a member of the Beccles Town Council and trustee of Beccles Museum, said his knowledge of Beccles history did not go back as far as 4,000 years, so he was very interested to find out what would come of the investigation.

"A few of us hope to be going out to the site soon," he said. "It would be good if any finds are locally significant and don't need to be held elsewhere, to see them go to Beccles Museum."