British Gas has picked up the 40,000 contracts of BizzEnergy after the collapse of a second independent energy supplier in the last month.

Worcester-based BizzEnergy, which supplied electricity to UK businesses, appointed KPMG Restructuring as administrators on Friday and 120 jobs were subsequently cut from its 168-strong workforce.

But British Gas has since acquired BizzEnergy’s customer base, ensuring continuity of supply to existing customers on current terms.

The company’s collapse raises concerns about the difficulty of breaking into Britain’s energy supply market, which is dominated by six major players. Jonathan Elliott, managing director of energy broker Make It Cheaper, said: “The departure of BizzEnergy is another knife wound to competitiveness in the UK energy market.

“The regulator [Ofgem] now has to act fast to reassure businesses that the Big Six will not be allowed to continue operating as a cosy oligopoly.”

Last month another independent supplier – Electricity 4 Business (E4B) – went into administration, falling into difficulty partly as a result of soaring wholesale energy prices.

The collapse caused Ofgem to launch a supplier of last resort process for E4B’s customers. But because British Gas Business has bought BizzEnergy’s customer base, Ofgem will not need to invoke the process in this case.

Mark Orton, of KPMG, said: “We are pleased to have been able to enter into this agreement with British Gas Business as it means that customers will largely be unaffected by BizzEnergy’s insolvency.”

This week it was reported that thousands of businesses in the Midlands have been left paying emergency rates on their energy bills after the collapse of Electricity4Business. All 3,352 E4B customers in the region were placed on emergency rates at British Gas Business by Ofgem when the energy supplier went into administration.