Darlington'S most senior engineer is retiring at the end of the month after more than 30 years with the council.

During that time, Jim Gordon has been involved in major projects such as the construction of the inner ring-road, the riverside revival, the Market Place restoration and the new football stadium.

His work has provided the background for research which is rewarded today when he is presented with a PhD by Durham University.

Using the geology and archaeology uncovered during the building projects, Mr Gordon has been trying to work out why the first Darlingtonians settled beside the River Skerne.

He said: "I tried to find out where the original core of the town was. The people would have needed a good water supply and to be near the river but above the flood plains.

"Then I looked for clues in the town lay out, to see if it dated back to Mediaeval times and beyond.

"Bringing all these things together, I am confident that the ancient centre of the town was at one end of Skinnergate or the other. Some people say it was Bondgate, but I think it was Blackwellgate - although there is still a lot of work to do."

Mr Gordon, 58, is from Coundon, near Bishop Auckland. He came to Darlington in 1970 as a newly-qualified chartered civil engineer, having worked for the Durham Water Board, Morpeth council and Aycliffe Development Corporation. He became acting borough engineer in 1987 - a post he effectively still holds although council reorganisations have engineered him a variety of titles.

He said. "The project I am most proud of is the Market Place refurbishment of 1994 to 1996. It was a scratty car park when we started, but we restored its historic boundaries as they were in 1855."

The lighting columns around the Market Place were designed to include references to the town's many coats of arms over the centuries.

"We restored the St Cuthbert's churchyard wall, its ironwork and its stone finials," said Mr Gordon.

During that process, 32 Mediaeval bodies were uncovered just outside the churchyard gates. "Their remains were placed back under the wheel beside the Boot and Shoe pub," said Mr Gordon. "The wheel is copied from Locomotion No 1 because we wanted to pay homage to the railways."

Mr Gordon is setting up as a project management consultant. He is to advise Darlington council on the football stadium being built in Neasham Road.