There is no group more likely to vote than the elderly. Unfortunately for Labour, it is among them that it performs worst. In the latest YouGov poll, the party trailed the Conservatives by an elephantine 45 points among the over-65s. Unless this performance is dramatically impoved, the opposition will remain a stranger to power.

Mindful of this, Labour will tomorrow attempt to improve its standing with the launch of its Pensioner’s Pledge Card. The party will promise to maintain the triple lock on the state pension (so that it rises by either earnings growth, inflation or 2.5 per cent, whichever is highest) until 2025, to compensate women affected by the increase in the pension age, to protect the pensions of UK citizens living abroad and to preserve the universal Winter Fuel Allowance and free bus passes.

The card is a knowing echo of New Labour's 1997 edition (an aide to John McDonnell quipped that he was looking for his copy) and an attempt to open a dividing line with the Conservatives. To the consternation of some Tories, David Cameron repeatedly refused to cut pensioner benefits. "I'm not having one of those bloody split screen moments," the former prime minister would tell aides. By contrast, Theresa May and Philip Hammond have refused to rule out removing the costly triple lock in the next parliament. In his Budget earlier this year, Hammond signalled a review of the policy by warning that "we will need to ensure that we tackle the challenges of rising longevity and fiscal sustainability".

Unlike Ed Miliband, who pledged to remove the Winter Fuel Allowance from the wealthiest 5 per cent of pensioners, Labour is now seeking to outflank the Conservatives. The party first pledged to maintain the triple lock last December but aides acknowledge the promise was insufficiently promoted. During a visit to Age UK Coventry’s Craft and Computer Centre, McDonnell will say: "I am delighted to be launching this pledge card that will inform many elderly people in our communities that Labour is not only promising to stand up for pensioners; but is determined to ensure they keep the hard-won entitlements they currently hold.

"It’s a national scandal that pensioner poverty is rising and the Tories are refusing to commit to keeping the triple-lock or compensate women worst affected by the speeding up in the state pension age.

"Only a Labour government will stand up for pensioners and protect them throughout the next parliament."

The party will also publish new analysis from the House of Commons Library showing pensioners will be at least £650 better off by 2025 from the maintenance of the triple lock. As part of its "economy week", Labour has already pledged to raise the minimum wage to £10 and to crackdown on late payments to small businesses. The week before it promised to levy VAT on private school fees to pay for universal free school meals. Internal opponents of Jeremy Corbyn acknowledge that the policies are clear and appealing.

Rather than rejecting any of the individual proposals, the Conservatives have focused on challenging Labour's wider economic credibility. Tory MP Kelly Tolhurst said in response to the Pensioner's Pledge Card: "Labour’s economic mismanagement hit older people hard when they were in government, and Jeremy Corbyn and John McDonnell’s reckless plans would do the same all over again.

"Our careful management of the economy, changes to help people save more for their retirement, and protections for pensioner benefits and the State Pension are all helping people have dignity and security in retirement."

However popular some of Labour's policies may be, the Conservatives can be confident of retaining power as long as they maintain their vast poll lead on leadership and economic management. In a recent ICM survey, May and Hammond led Corbyn and McDonnell by 31 points as the best economic team. Though the voters may like the message, Labour's greatest challenge is convincing them to embrace the messengers.