Britain’s largest electricity distributor has confirmed a series of partnerships to help deliver £920m of investment in the network which delivers power to homes and businesses across the East and South East of England.

UK Power Networks, which maintains cables, substations and power lines serving more than a quarter of the UK’s population, has appointed six key contractors to work with it on ensuring the reliability and safety of power supplies over the next six years.

Avidety, Freedom, Morrison Utility Services, SPIE, Stormport Professional Services and Reach Active have been selected to work with UK Power Networks to refurbish and upgrade electricity substations and power cables, with the contractors also supporting the company’s own response teams during storms.

Brian Stratton, head of distribution capital delivery at UK Power Networks, said: “We have brought together contractors with complementary skills to help maintain and improve our networks while delivering great customer service in the most efficient, effective way.

“We will be investing in improvements to the performance of our electricity network and replacing assets to ensure the network remains safe and resilient for our customers. The overhead line contracts will also ensure we have additional storm support, helping us recover as quickly as possible from emergencies.”

Overhead power line contracts, to be covered by Freedom and SPIE in East Anglia and ReachActive and Avidety in the South East, will deliver overhead line refurbishments up to and including 132,000-volts, electricity poles and component changes and help repair equipment if it is damaged by storms.

Services contracts, held by Stormport Professional Services and Freedom in East Anglia and Morrison Utility Services in the South East, will cover underground network investments, including replacing equipment in electricity substations, installing new electrical junction boxes, laying and commissioning new underground cabling and fitting out new substations, to improve the reliability of power supplies. They will also be working on overhead line projects, including support following storms.

UK Power Networks serves 28% of the UK’s population, delivering electricity to 8.1m homes and businesses via more than 28,000 miles of overhead electricity lines and around 87,000 miles of underground cables.

The company says it is investing £500mn this year alone to upgrade and maintain its networks as part of a £4.5bn investment programme for the eight years up to 2023.