The vandals damaged insulators at the tops of poles

Almost 4,000 electricity customers in the Murton, Ryhope and Seaham areas of Sunderland lost their power on Wednesday morning.

Engineers quickly restored the supply to most properties, but some homes were without power until mid-afternoon, said Northern Electric Distribution (NEDL).

The cable which was damaged carries 20,000 volts of electricity.

Brian Atkinson, area restoration�manager for NEDL, said: "The vandals are putting their own lives as well as the public at risk.

'Mindless vandalism'

"If they had brought down a live power line by their actions, someone could have been badly injured or even killed."

Insulators at the top of poles supporting overhead wires were targeted, causing the high-voltage cable to trip.

The section of overhead line runs alongside a public footpath close to a fishing pond in Murton called Sandy Hill.

In total, 3,748 people were affected by the power cut.

Mr Atkinson added: "This is the second act of mindless vandalism this month and is extremely dangerous as well as being a major inconvenience to our customers.