The human remains have now been removed and are being examined by archaeologists to determine their age and significance.

According to a letter sent to Hunmanby Parish Council by Yorkshire Water, the bones were discovered near Malton Road.

Yorkshire Water is spending £11 million installing a new pipeline connecting the water treatment works at Haisthorpe, near Bridlington, with another about 19 miles away at Irton, near Scarborough.

The project, which started last year, will offer the Filey and Scarborough areas an alternative supply of mains water in an emergency, thereby reducing the risk of interruptions in years to come.

Contractors laying the new pipe are also working closely with archaeologists to protect the region's rich heritage.

Evidence uncovered so far supports the story of significant settlement during the Roman occupation, not just by legionnaires but by indigenous people who learned to live with the invaders and even traded with them.

A spokesman for Yorkshire Water said: ''Protecting archaeology is an intrinsic part of most of our major schemes, particularly when we're working in areas with a rich heritage such as the Yorkshire Wolds and the Vale of Pickering and uncovering historic remains comes as no surprise.

"The significance of this find has yet to be established.

"The remains could date back to the Bronze or Iron Age, but details are scant at the moment and the team working on the dig will need time to establish the facts – a process which can take weeks or even months.

''In the meantime, Yorkshire Water will continue to work with Northern Archaeological Associates on a public event planned in late spring when all the significant finds made along the route of the East Coast pipeline will be on display to the public and full details will be given on their likely origins and use.''