Malcolm Turnbull has broken cabinet secrecy to reveal the deliberations over delaying his national energy policy and his fears it could lead to higher emissions and higher electricity prices.

Accusing his former Coalition colleagues of being “bedevilled by ideology and idiocy”, Mr Turnbull admitted he gave it his best shot but effectively could not beat the climate-change deniers, who threatened to “blow the show up”.

But he urged Prime Minister Scott Morrison to listen to himself and Julie Bishop and revive the National Energy Guarantee. 

The former Prime Minister offered what he described as a candid assessment at an energy conference in Sydney on Tuesday. 

“Part of the problem with the politics of energy … it has been bedevilled by what I would call ideology and idiocy,” he said. 

“There are people who will look you in the eye and say coal-fired power is cheaper, new coal is cheaper. And you say, ‘OK, what price of coal are you assuming?’. Crickets.

“This is not a religious issue. It’s an issue that’s got to be grounded in engineering and economics.”

But it is grim news for his successor. Mr Morrison has desperately tried to reset the debate on his government by banning the coup culture in Canberra.

On Tuesday, Mr Turnbull supported that move.

“You can say they are better late than never but you can’t live your life backwards,” he said in Sydney. 

Mr Turnbull said the media would seek to sensationalise his latest comments but it was simply a fact. 

“It (the NEG) did have overwhelming support of the party room and, indeed, the cabinet. There was a minority of Coalition MPs who effectively torpedoed what was a very good, technologically agnostic policy,” he said. 

“I just want to note that I did not abandon the NEG as our policy. In fact, it remained. But in the frantic last week of my prime ministership, the insurgency, which of course undermined it and ultimately brought it to an end, the cabinet resolved not to introduce the legislation until we were comfortable we could secure its passage.” 

Mr Turnbull said the government could not countenance having a key piece of economic legislation defeated in the House of Representatives. 

“It had strong support. And none stronger, I might add, than the current Prime Minister and Treasurer,” he said.

“Anyway, that was very disappointing. 

“Like Julie Bishop and many others, I would encourage – at the risk of being criticised for talking about politics, which apparently former prime ministers are not allowed to do – I would strongly encourage my colleagues to work together to revive the National Energy Guarantee.

“I don’t want us to get to a situation where we have higher emissions and higher electricity prices.” 

The former prime minister also took a swipe at former Nationals leader Barnaby Joyce. 

“There is a huge gulf. There is a significant percentage of the Coalition members who do not believe climate change is real. There are even some who rather the government, instead of building Snowy 2.0, build a coal-fired power station,” he said.  

“Barnaby Joyce made that helpful suggestion in the final week of the Wentworth campaign.”

Meanwhile, the ban on prime ministerial coups has also won the support of another former PM, Tony Abbott. 

“It’s a very sensible move by the Prime Minister and he’s got my full support,” Mr Abbott said. 

Even Liberal Party elder John Howard, who recently said he didn’t support such a change, has lauded Mr Morrison’s decision.

“I think they will be widely acclaimed in the Liberal Party,” he said.