A Labour government with a huge majority will rig the electoral system to keep themselves in power for “decades”, Rishi Sunak will claim as he tries to scare voters ahead of polling day on Thursday.
The desperate prime minister will even say Keir Starmer - the former Director or Public Prosecutions - will give prisoners the vote to stay in power.
He will say there are “four days to save Britain” and repeat discredited claims that Labour would put up taxes by £2,000 per household.
Sunak’s bizarre comments, at an election rally on Monday night, come as opinion polls continue to predict a Tory wipeout.
Elections guru Professor Sir John Curtice told the BBC on Sunday that the Conservatives could be left with just 100 MPs, compared to Labour’s 450, come Friday morning.
In a last-ditch attempt to avoid annihilation at the ballot box, the PM will beg voters not to hand Labour a “supermajority”.
That is despite polling evidence that tactic has backfired by making voters more likely to back Starmer’s party.
The PM will say: “We have four days to save Britain from a Labour government.
“Labour would hike taxes by more than £2,000 for every working family, would shunt our politics to the left and change the rules to ensure that they can stay in power for decades.
“If they get the kind of majority, the supermajority that the polls suggest, they will set about entrenching themselves in power.
“They will rewrite the rules to make it easier for them to stay in office and harder for anyone to replace them.”
He will add: “We already know that they want to give 16-year-olds the vote. They don’t want to do that because they think they are adults, but because they think they will vote for them. What other changes will they make to make it harder to remove them from power?
“Votes for EU nationals? Votes for prisoners? A whole new voting system designed to allow politicians to stitch things up behind closed doors and shut you out?
“Don’t let them do that. Don’t take that risk. Don’t surrender to Labour.”
The prime minister’s warnings are similar to the unsuccessful scare tactics - dubbed “Project Fear” - used by the Leave campaign during the 2016 Brexit referendum.