Nearly 1 million people aged over 66 in the UK are living in deprivation, according to government statistics, the highest number since comparable records began.

Labour, which analysed figures from Department for Work and Pensions (DWP) records, has vowed to be the party for pensioners, with plans to insulate millions of homes and reduce energy bills. It has also “committed to retaining” the triple lock which guarantees annual rises to the state pension.

But both Labour and the Conservatives are under pressure to do more to help the poorest, as the number of over-66s experiencing deprivation is growing despite the triple lock.

Separately, a report by the Fabian Society suggests the number of people over 60 living in poverty who are not yet eligible for a state pension has tripled since the Conservatives came to power in 2010.

The thinktank said ministers had in effect abandoned more than 1 million older people who lacked support to stay in work or to retire. It found that between 2010 and 2022, the number of people living in poverty aged between 60 and the state pension age had ballooned by about 800,000 to 1.2 million.

Sasjkia Otto, a senior researcher at the Fabian Society, said: “This silent crisis was caused by government policy decisions, so ministers should take responsibility for finding solutions.

“As things stand, the government assumes that people in their early and mid-60s can keep working and earning just like those in their 20s. This is true for lots of people and we should celebrate those who defy harmful ageist stereotypes. But many others in their 60s face long-term barriers to work, including sickness, disability and caring responsibilities.”

Rather than poverty, the DWP figures analysed by Labour measure deprivation levels: people aged 66 or over across the UK were asked whether they had access to basic goods and services, including substantial meals, heating and electricity, a home that was in a good state of repair, and contact with friends and family at least once a month.

Of 977,386 over-66s who were experiencing deprivation in 2022-23, 100,000 were living in working households.

The figures suggest the number of older people experiencing hardship has risen by more than a third since before the pandemic, although the DWP advises against making a direct comparison with the Covid-19 period because data collection was affected by restrictions.

The figures demonstrating the extent of deprivation among older people in the UK contrasts with the controversy about the cost of the pension triple lock, which was introduced by the coalition government in 2011-12.

The triple lock increases the state pension every April in line with either the previous September’s level of inflation, the amount by which wages have increased, or 2.5% – whichever is highest. In April 2024, the state pension rose by 8.5%, the amount by which wages rose.

In the past year there have been calls to change the system because of its cost to the public purse. A report by the Institute for Fiscal Studies last year found that maintaining the triple lock could add as much as £45bn a year to the welfare bill by 2050, putting “insurmountable pressure” on the government to increase the minimum retirement age.

The former Tory leader William Hague described the policy as a “runaway train” that was creating a dangerous social and political situation by denying younger generations a fair stake in the economy.

Jeremy Hunt, the chancellor, has said the Conservatives would keep the triple lock system if they won the election. A Labour spokesperson said the party was “committed to retaining the state-pension triple lock”, though it has yet to confirm whether the pledge will feature in its election manifesto.

The shadow work and pensions minister, Alison McGovern, said the DWP figures were “the disgraceful consequence of 14 years of Tory misery”.

“The Tories crashed the economy, causing a cost of living crisis for which pensioners are still paying a heavy price,” McGovern said. “Now their reckless £46bn unfunded proposal to cut national insurance risks leaving pensioners even worse off with their refusal to say how they will pay for their plan or whose taxes will have to go up.

“The country is crying out for change. It’s Labour who have the plan to grow the economy, to tackle the cost of living crisis, and to once again be the party for pensioners.”

Labour has pledged policies that would benefit over-66s, including a plan to insulate 19m homes in a decade, which would reduce energy bills. It has also committed to creating a publicly owned body to invest in clean energy.

State pensions are paid every four weeks to people who have reached the qualifying age, currently 66, and have paid enough national insurance contributions. The state pension age is set to rise to 67 in May 2026.

According to a House of Commons library report from 2022, the UK provides a lower state pension than most other advanced economies relative to average earnings.

A DWP spokesperson said: “We do not accept this characterisation. We are committed to backing all pensioners, and since 2009-10 there are 200,000 fewer pensioners in absolute poverty after housing costs.

“With the aftershocks of Covid and the war in Ukraine driving up inflation and cost of living pressures, we provided unprecedented support worth £3,800 per household, as well as additional cost of living support preventing 400,000 pensioners from falling into poverty in 2022-23.

“And we will keep supporting pensioners, which is why we have delivered a further increase of 8.5% this month through the triple lock following last year’s largest ever cash increase, taking the full rate of the new state pension to more than £11,500 a year.”