The owner of British Gas has called for rival Octopus Energy to be banned from taking on new customers amid an industry spat over new cash requirement rules.

Chris O’Shea, the chief executive of Centrica, claimed new financial resiliency requirements were not being properly enforced as he accused the regulator Ofgem of “criminal” double standards.

He said suppliers who were not meeting the new capital rules already should be prevented from accepting new customers until they do so amid fears they may pose a “systemic risk”.

This would include Octopus, which overtook British Gas to become the UK’s biggest supplier of gas and electricity in January.

Mr O’Shea insisted his comments were not “sour grapes”, but about ensuring regulatory rules were “fair and evenly applied”.

He said: “You can have a look at Octopus Energy’s accounts yourself, and you can see that the shortfall is over £1bn.

“So you’ve got to ask yourself – why do they not do what we’ve done? That’s all we think. We think that when the regulator brings out rules that they should equally apply them.”

He also lashed out at Ofgem for presiding over a “multi-tier system” and accused the regulator of already costing consumers more than £100 through its bungled handling of the 2021-22 energy crisis.

Mr O’Shea added: “They’re increasing the chance of systemic failure in the market.

“And that cost billions of pounds years ago, and Ofgem’s fingerprints were all over that.

“I think it is criminal that they are sitting in a situation where that thing could happen again.”

On Thursday, Octopus said it was not in breach of Ofgem’s cash rules. A spokesman said: “This is yet more naked self-interest from British Gas. They would do well to obsess about their customers rather than their rivals.

“We fully comply with Ofgem’s rules and our resilience meant we not only thrived through the energy crisis but bailed out Bulb – saving British billpayers billions.”

A spokesman for the regulator also stressed that the rules allowed for companies to agree a plan to reach the capital buffers over time.

The rules introduced by Ofgem this year require energy companies to keep cash in the bank as a safety net, in case customers can’t pay.

It imposes a capital “floor” of zero pounds per customer, meaning suppliers should not be running on negative capital, and tells suppliers to aim for £115 per customer as the ideal amount.

Three energy suppliers have so far failed to hit the new requirements, which came into force in April.

Octopus, which supplies more than 7m households, confirmed it was one of them but said it had agreed a path to compliance with the regulator.

Tomato, a much smaller provider with only 12,000 customers, has also failed to meet the requirements. It was banned from taking on new customers in April amid concerns about its multimillion-pound debt pile.

The third energy company not meeting the rules has not been publicly confirmed.

Mr O’Shea lashed out against Ofgem, arguing that suppliers that had not met the requirements should be prevented from growing.

He said the case of Rebel Energy, which went bust with 90,000 customers before being taken over by British Gas, underlined the need for the rules.

Mr O’Shea added: “They gave suppliers just over two years to meet that. And most suppliers did.

“But there were three that didn’t ... They have recently stopped a supplier called Tomato from taking on new customers. But they haven’t stopped the others that haven’t met this from taking on new customers. And we think that is outrageous.

“We think that Ofgem are not applying their own rules consistently, and they’re creating multi-tier regulation.”

It marks the latest twist in the long-running battle between British Gas and Octopus.

Mr O’Shea and Greg Jackson, the founder and chief executive of Octopus, have previously clashed over issues such as zonal electricity pricing.

On Thursday, Ofgem rejected suggestions that it was not enforcing its own rules properly.

A spokesman said the regulations meant companies must either meet the capital buffer requirements or have an agreed plan in place to meet them within a set period of time.

A spokesman for Ofgem said: “Our financial resilience controls are clear that where a supplier is not meeting the capital target but has a credible and agreed plan in place, that is not a breach of the rules.

“Capitalisation plans come with restrictions and controls. We expect suppliers to deliver on those plans and adhere to their restrictions and are monitoring closely.”

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