Electricity and gas supplier Octopus is to take on 1.4million more household customers after it acquired Shell's energy business in the UK and Germany.
The deal brings Octopus's total customer base to 6.5million homes - around one million behind Centrica-owned British Gas, the UK's largest supplier.
Octopus's customer base in Germany will grow to almost 300,000.
The transaction, which is expected to be completed in the final three months of this year, also includes 500,000 broadband customers.
Shell customers will be contacted about the switch to Octopus once the deal gains regulatory approval.
Octopus - the only Which?-recommended energy supplier in the UK - had already grown significantly following the acquisition of Bulb's customers in October last year, adding 1.5million customers.
Stringent process
Greg Jackson, the chief executive, said: "Following a stringent process, we are pleased to be acquiring Shell Energy Retail in the UK and Germany.
"Octopus has proven that it delivers game-changing service whilst innovating and investing relentlessly towards a cheaper, cleaner energy system.
"Our commitment to customers is paramount and we will do whatever it takes to deliver the Octopus promise when we welcome these new customers too."
The Telegraph says the sale to Octopus means Shell will exit the household supply sector after just six years.
The company first entered the UK home-supply market in 2017 when it acquired energy and broadband provider First Utility and the firm's 825,000 customers.
Footprint expanded
It later expanded its footprint with the acquisition of Green Star Energy and the Post Office's energy business, as well as agreements to take on some customers whose suppliers collapsed in the face of rising prices in the wake of the war in Ukraine.
Steve Hill, executive vice-president at Shell Energy, said: "This agreement follows the announcement during our Capital Markets Day to divest our home-energy retail business in Europe.
"To drive performance, discipline and simplification, we are prioritising countries, projects, and routes to market where we can deliver the most value.
"We will work closely with Octopus to ensure a seamless transition and continued high standards of customer service."
FTSE 100
The UK's top share index, the FTSE 100, was up 39 points at 7,503 shortly after opening this morning, following Friday's 25-point rise.
No FTSE 350 companies are due to report today.
Brent crude futures were down 0.12% at $88.48 a barrel.