Shell is taking on the customers of collapsed energy company Green Supplier as the sector's crisis strengthens larger, more resilient players.
Green Supplier's 255,000 customers are being transferred to Shell Energy after the Newcastle-based company, whose headquarters are in the city's former coroner's courts, went bust last week.
In the company's last set of full accounts, up to November 2020, it had £6.24m in net liabilities on its balance sheet, four directors and no employees.
Shell launched its UK retail business, supplying electricity and gas to households, in 2018 after acquiring First Utility for about $200m (£146m).
At the time, First Utility had more than 800,000 customers and was the largest of the country's new wave of "challenger" energy suppliers, who were meant to shake up an industry dominated by a handful of large players. A year later, First Utility was rebranded as Shell Energy.
But a surge in wholesale gas and electricity prices in recent weeks has seen six of the country's small energy suppliers collapse. Industry watchdog Ofgem's chief executive warned MPs last week that more would go bust in the coming months.
Ofgem has said any outstanding credit balances, including money owed to both existing and former domestic customers of Green Supplier, would be honoured, and price caps would stay in place.
"We understand that this news may be unsettling for customers, however they do not need to worry. Their energy supply will continue as normal, and customer credit balances will be honoured," said Neil Lawrence, Ofgem's director of retail.
"Shell Energy will be in contact with customers over the coming days with further information. Once the transfer has been completed, customers can switch if they wish to."
Ofgem chose Shell Energy after running a competition between other energy businesses. It will take the number of Shell customers to more than 1.1m.
Ed Kamm, chief executive of Shell Energy retail, said: "We are a well-capitalised supplier with long term ambitions to help British households get to net-zero emissions. We've made it clear to Ofgem and the department for business, energy and industrial strategy that we are ready to play our part and help support customers of failed energy suppliers."
On Sunday Octopus Energy took on Avro Energy's 580,000 customers, after Avro went under. That takes the total number of Octopus customers to 3.1m, making it the UK's fifth largest suppler by number of customers, just six years after it was founded.