Boris Johnson and Liz Truss have rebelled against Rishi Sunak in yet another headache for the current PM.
The former Prime Ministers have called for a government U-turn as their successor struggles to hold the party together.
He already faces a backlash from within Tory ranks over his government's controversial tax rises and was forced to pull a vote over mandatory housebuilding targets scheduled for next week.
Now another split has opened up on wind farms.
In the latest setback for the PM, both Mr Johnson and Ms Truss have called for a ban on onshore wind farms to be lifted - despite the former supporting it when he was in office.
They have backed an amendment to the government's Levelling Up and Regeneration Bill put forward by Tory MP Simon Clarke.
Mr Clarke bragged on Twitter : "Delighted to have the backing of Boris Johnson and Liz Truss, together with MPs from right across the Conservative Party, for my amendment to allow onshore wind where (and only where) there is community consent.
"A pro growth, pro green policy at a time when we need both."
The ban was brought in by David Cameron in 2015, and Ms Truss promised to lift it during her brief spell as Prime Minister.
If Tory rebels get their way, government guidelines will be changed to allow onshore windfarms, which are one of the cheapest forms of renewable energy.
Mr Clarke told the Financial Times : “I think there is such a compelling case in terms of economic, environmental and political rationale as well as energy security, to put decisions on wind farms in the hands of local communities rather than having a hardline block.”
Sam Hall, director of the Conservative Environment Network, told the newspaper: “Onshore wind is one of the cheapest sources of energy generation, polls show it is popular with voters, including Conservative voters, including those in the countryside.
“The current system – which allows an objection by just one person to stop a new development – is not conducive to helping us tackle our energy crisis and get more home-grown energy.”
