Jacob Rees-Mogg has suggested Boris Johnson was right to take a thinly-veiled swipe at Rishi Sunak earlier today.
The Prime Minister made the remark in front of an audience in Birmingham, when he quipped that slashing VAT from energy bills would be "easier than we thought".
Mr Rees-Mogg, the Minister for Brexit Opportunities, claimed that many in the Cabinet including Mr Johnson supported doing this months ago - but were blocked by Mr Sunak.
The former Chancellor, who is trying to become the next Tory leader, was accused of a screeching U-turn over VAT - having previously opposed the move.
He implied that the PM - who will leave office on September 6 - would have supported the move, as would other members of the cabinet.
This afternoon Mr Rees-Mogg told Times Radio: "I think the Prime Minister was puzzled as to why that wasn’t policy earlier in the year when the Prime Minister and other members of the cabinet, including me, thought it was an extremely good idea but it wasn’t so popular in 11 Downing Street.
"So times change and we change with them, as they say."
Speaking at the Commonwealth Business Forum in Birmingham, the outgoing PM said: "I'll give you this assurance, they will continue with the same programme, cutting taxes, simplifying regulation as much as possible, taking advantage of all our new regulatory freedoms, getting rid of every encumbrance from solvency to MiFID to VAT on fuel - turns out to be easier than we thought."
It comes as Mr Sunak and Liz Truss slug it out in a bitter contest to become the next Tory leader.
Yesterday the Institute for Fiscal Studies (IFS) cast doubt on Mr Sunak's VAT plan - saying the biggest benefactors would be high users rather than those struggling to pay.
The IFS said once introduced it would be tricky politically to bring VAT back - but said if it became permanent it would move the UK in "exactly the wrong direction".
It is estimated that scrapping VAT on energy bills would save households around £156 a year, with the cost to the exchequer estimated at around £4.3 billion.
While this would be "bearable" in the short term, it could encourage more energy use if brought in over a longer period, an expert said.
Stuart Adam, a Senior Economist at the IFS, said: “By providing more support to those who use more energy, it would be well targeted at those who face the biggest rise in their energy bills, but not at those – the poorest – who are least able to cope with the rise in costs.
"If it were genuinely temporary, the fiscal and environmental costs of the policy would be bearable.
"The biggest risk with the policy is that it would prove politically difficult to restore VAT on energy bills at the end of the 12 months.
"As a permanent policy, removing VAT on energy bills would be a move in exactly the wrong direction: distorting households’ choices towards more energy use, making it harder to meet the UK’s ‘net zero’ targets and meaning that any reduction in emissions happened in a way that was more costly overall to households than it need be."
In January a Labour motion to force a cut in VAT on energy bills was voted down by Tories, with Boris Johnson previously branding the move a "blunt instrument".
Mr Sunak said: "Tackling inflation and getting people the support they need to help with the cost of living is critical.
"That’s why, with the price cap expected to rise above £3,000 in October, I will move immediately to scrap VAT on everyone’s domestic energy bills for the next year, saving the average household £160.
"This temporary and targeted tax cut will get people the support they need whilst also – critically – bearing down on price pressures."
