Primitive tools hidden for thousands of years have been unearthed during a project to remove electricity poles in Malham.

The Yorkshire Dales National Park Authority (YDNPA) is working with Electricity North West, which manages and owns the region’s power network, to reduce the visual impact of overhead powerlines and electricity poles on the National Trust’s Malham Moor Estate by laying the cables underground.

And dozens of prehistoric flints were found during the first phase of the £300,000 project, which will remove 23 electricity poles and replace overhead powerlines with 2.2km of underground cable.

Work was temporarily put on hold while archaeology students from Bradford University carried out an investigation under the supervision of Dr Randolph Donahue.

Mark Newman, the National Trust’s consultant archaeologist, said: “The excavations have provided wonderful evidence of how the Yorkshire Dales have been attracting visitors for thousands of years.

“We knew that Malham Tarn was an ideal summer hunting ground in the Mesolithic period particularly, because of the number of wildfowl on the water and the range of good-quality grazing that attracted game around the tarn.

“It was a summer hunting camp – a site that was visited again and again over the course of thousands of years. The hunters lived very sustainably and used materials extremely sparingly so the majority of the items Dr Donahue’s team found were tiny parts of small flint tools.

“There will be another phase of work when we go along and see what else is uncovered. We really value the support we have received from the national park authority and from Electricity North West in a project that is going to enhance the landscape and tell us more about its past.”

Mike Dugdale, programme delivery manager for Electricity North West, said: “Whenever we’re putting cables underground in an area known for its rich history we check for any important archaeological artefacts. These prehistoric findings are an exciting and important discovery.

“We put the project on hold until investigations were carried out, but we’re planning to start work again by March.”

The power project forms part of a £5.4m five-year scheme to remove overhead electricity lines identified as being most visually intrusive within the national parks and areas of outstanding natural beauty in the North West.

Tom Harland, the YDNPA’s planning policy officer, said: “The main aim of the scheme is to reduce the visual impact that electricity lines have on the landscape.

“However, we also have to weigh up the potential impact of the work on archaeological features, wildlife and local people. In this case, the work has helped to improve our understanding of some very important archaeological sites and to choose a route for the trench that avoids them.”