One of the most important archaeological finds for decades has been uncovered during a sewer improvement project in Poulton.

The remains of a Roman roundhouse, thought to date back to the second century, have been discovered on grazing land close to the town.

The find was made by workers from United Utilities who were involved in preliminary excavations at the start of a £10 million sewer improvement scheme for the area.

As is common when a major excavation starts, an archaeologist was present in case any important finds were made. Within a couple of hours of work beginning on the land off Garstang Road East, Poulton, it was obvious a significant discovery had been made.

"As the topsoil was stripped away, we realised we were looking at something very exciting and rare," said Alison Plummer, from the Lancaster office of Oxford Archaeology, archaeological consultants for United Utilities.

A team of 10 archaeologists is now working at the football pitch-sized site, painstakingly uncovering and documenting what remains of the Romano-British roundhouse which is around 10m in diameter.

A small amount of black burnished ware pottery, thought to date from around the second century, has been found which has helped the experts to date the roundhouse.

The remains of the house, which would have been a dwelling house, include an outside drainage gulley, holes for the timber support posts which would have been used, some cobbles and a storage pit.

The archaeological team believe they have also discovered signs of a further roundhouse a few metres away, indicating this could have been the site of an early settlement.

"Finds like this are very rare in Lancashire, and especially rare in this area," said Alison. "There are only two other Roman roundhouses that we know of in the county, one outside Lancaster and one near Lathom.

Andy Pennick, an environmental planner for United Utilities who is involved in the sewer improvement scheme, said: "Having archaeologists along during excavation is all in a working day for us and it's not often anything very unusual crops us. But this is something different and we're all pretty excited about the discoveries."

Archaeologists will be on site for the next two weeks documenting every detail of their finds and taking photographs which will eventually form the basis of an information archive.

Archaeologists and United Utilities are holding an open day at the site between 11am and 3pm on Thursday, March 27 for members of the public to see the discoveries.

They have appealed to people to keep away at other times in case the site is disturbed.