The full state pension for a single pensioner is £9,110.40 a year but figures show the average spending for a one-person retired household is £12,766, leaving a shortfall of £3,656.

This means today is the day a retiree’s average yearly spending starts to exceed their annual state pension, so the gap will need to be plugged by other sources of income, such as a private pension or other savings and investments.

Couples receive double the state pension (£18,220.80) and are estimated to spend £25,932 a year on average. This represents a shortfall of £7,712, and means without other sources of income, they would run out of money earlier – by 12 September, according to calculations by Just Group.

Stephen Lowe, group communications director at Just Group, said the data highlights the shortcomings of the state pension for pensioners who rely on it for their sole source of income but still hope to maintain a decent standard of living in retirement.

He said: “It illustrates the importance of building up other savings to provide additional income when they are no longer working.

“It’s a reminder that putting off saving or opting out of a workplace pension scheme can leave people struggling for income in later life. And those thinking of accessing pensions cash before they retire will want to consider what that might mean for their income in a few years’ or decades’ time.

“The government’s free, independent and impartial guidance service – Pension Wise – helps people approaching retirement to understand their options better. Before tapping into pension savings, we urge all adults to make use of the service, it is proven to improve people’s knowledge of their retirement options and equip them with greater confidence to make good decisions about their retirement finances.”

Lowe added that for those in retirement struggling for income they should find out what state benefits they might be entitled to as “large amounts go unclaimed”.

“A good online source is direct.gov.uk but Citizens Advice and other charities might also be worth contacting,” he said.

See YourMoney.com’s pensioner benefits guide for more information.