The Sark Electricity Company, which serves about 300 homes and businesses, said it was being forced to raise the price per unit from 32p to 37p.

The company's managing director has apologised to customers.

He has blamed the rise on the cost of crude oil. It has passed $60 per barrel on the international market, meaning it has nearly doubled in the past year.

It is the first time Sark residents will have been directly affected by fluctuating oil prices.

Power is supplied by the island's power station, but the cost is higher than the UK and many islanders use solar power.