Labour plan to use "Vote Rishi, Get Liz" to attack the Conservatives in the run up to the next general election.
Senior figures believe former Prime Minister Liz Truss is "toxic" with voters, the OceanNewsUK has been told.
Labour are currently leading opinion polls by a substantial margin.
The party intend to argue that if the Tories won a majority it would likely be small enough for prominent figures on the right of the party, including Ms Truss, to have a significant influence.
Last month, Labour posted a picture on X of Prime Minister Rishi Sunak in the pocket of his successor, alongside the caption: "We know who's really in charge."
For years, the Conservatives used a similar attack line against Labour.
When Ed Miliband, now the shadow energy secretary, was leader of the Labour Party the Conservatives repeatedly argued that a vote for Mr Miliband would be a "vote for the SNP".
Labour insiders are more confident they can rebut this attack line, following the swing back to Labour from the SNP in the recent Rutherglen and Hamilton West by-election.
But now, sources suggest they want to learn something from the Tories' former strategy.
Labour intend to make a similar case in the run-up to next year's general election - blitzing voters with the message that if they vote for Mr Sunak, that will pave the way for Ms Truss and allies of her in the party to have a substantial influence on policy.
They argue that the "maths" of where the opinion polls sit at the moment would mean it would be much harder for the Conservatives to win the sizeable majority they have enjoyed since 2019, and argue this leaves more room for factions of the party to exert control and influence.
Former Prime Minister Theresa May, for example, struggled to pass much Brexit legislation due to pressure - particularly from the right-wing European Research Group of MPs in her party.
The opinion polls started to really shift in Labour's favour after Ms Truss's "mini-budget" last year, which spooked the financial markets and led to higher interest rates.
