A large quantity of materials have been stolen from Norton Road, Daventry.
Between 4.30pm on Wednesday 3 June 3 and 7.30am on Thursday June 4 offenders dismantled a fence surrounding the temporary works compound, next to the electrical substation at the end of the road.
Once inside they forced their way into the site office and storage shed, and stole two petrol Stihl saws, two Wacker plates and a trench Wacker rammer, as well two 240v petrol generators.
They then drove into the adjoining land, where they cut through a 1000v electric fence and removed a large quantity of single copper XLPE cable.
It is believed the offenders were driving a twin-axle van.
Witnesses or anyone with information about this incident is asked to contact police on 101 or Crimestoppers anonymously on 0800 111 222.