Octopus Energy has confirmed that it will buy its smaller rival Bulb after the UK government approved a deal.

Bulb has been kept in operation by the government since last year after it became one of more than 30 casualties of rising gas and electricity prices.

Following the transfer to Octopus its 1.5 million customers will not experience “any change or disruption to their energy supplies”, said the government.

It has been run by regulator Ofgem through a process known as “special administration” because at the time another company could not be found take over its customers.

The estimated £2bn of taxpayer support was the biggest state bailout since the Royal Bank of Scotland collapse during the 2008 financial crisis.

Octopus said the move would bring “an end to taxpayer losses”, adding it was “paying the government” to take on Bulb’s customers. The deal is expected complete by the end of November.

Business Secretary Grant Shapps said the move will bring “vital reassurance and energy security to consumers across the country at a time when they need it most”.

Alan Whitehead, Labour’s Shadow Energy Minister, said:  “The government needs to come clean about how much the collapse of Bulb has cost people in higher bills; what this sale will add to that tally; and how they have concluded that this deal represents value for taxpayer’s money. 

“Billions has already been added to consumer bills from 32 companies going bust. The Conservatives can’t shirk responsibility when the UK is the only country in the world where this has happened.”

Richard Neudegg, director of regulation at Uswitch.com, said: “Bulb’s customers have been in limbo for almost a year, without any clarity on what would be next after the supplier entered Special Administration. Today’s announcement draws a line under that uncertainty.

“The most important thing for Bulb customers to know is that their energy supply will continue as normal, and any credit balances will be protected.”