Sir Keir Starmer sparked a backlash after refusing to guarantee that the state pension triple lock will feature in Labour’s manifesto.
The Labour leader insisted he believed in the policy but would not follow the Tories in making an election commitment.
Matt Vickers, deputy chairman of the Conservative Party, said: “Labour can’t say what they would do on pensions because they don’t have a plan.
“With Sir Keir constantly refusing to commit to the triple lock, and his new tax tsar calling for hikes on pensions, it’s clear that Labour can’t be trusted to protect our pensioners.
“The Conservative Party is sticking with the plan and backing the triple lock. Labour would only take us right back to square one.”
Dennis Reed, director of the Silver Voices campaign group, warned Labour is “making a rod for its own back by refusing to commit wholeheartedly to the triple lock”.
He said: “I’m sure there will be some reference to the triple lock in their manifesto as to do anything else would lead to older votes flooding away from Labour.
“However, because of Sir Keir’s vague remarks, I am now suspicious that their manifesto will be equivocal on the subject, perhaps committing to the principle of it but leaving open the possibility of change.
“Older voters wouldn’t be fooled by that Sir Keir, we want an unequivocal commitment to the full implementation of the triple lock for the whole of the next Parliament.
“Until our miserably low state pension is improved, the triple lock remains an essential safeguard against pensioner poverty.
“Tell us now, because we are already in the general election campaign, and many voters will have made up their minds before the manifestos are published.”
Under the triple lock, state pensions rise every year in line with whichever is highest out of wage growth, inflation or 2.5 percent.
Chancellor Jeremy Hunt last month confirmed the pledge will feature in the Tory manifesto and remain in place throughout the next Parliament if the Conservatives stay in power at the next general election.
But Sir Keir would not go as far and said voters would have to wait to see Labour’s election manifesto.
He told the i newspaper: “I believe in the triple lock, committed to the triple lock, we certainly think this Government should continue with it.
“Precisely what’s in our manifesto, I’m afraid you’ll have to wait for the manifesto on that, because we will be setting out a fully funded manifesto. But I believe in the triple lock.”
“The final position will be set out in the manifesto because every commitment we make will be fully costed and funded, and that is the iron rule for whatever the issue is.”
Lord Foulkes, a Labour peer who is co-chair of the All-Party Parliamentary Group for Ageing and Older People, insisted there is “no way that the Labour Party will not at least match the Tories on this”.
He said: “Keir Starmer and Rachel Reeves are understandably not giving manifesto commitments at this stage on any spending given the financial chaos they are likely to inherit from the Tory Government.”