State pensioners with a 66th birthday that falls between June 6 and July 5 will lose out on up to £3,136.89 on average in pension payments due to a three-month rule.

A recent law change means the State Pension age in the UK is currently in the process of rising from age 66 to 67, but the change is being introduced gradually over a two-year period. The process got underway at the start of the new tax year on April 6 and is due to be complete by 2028, and will impact people due to turn 66 within this timeframe. Normally, you can start claiming your State Pension when you reach age 66 and can apply for it once you are within four months of State Pension age.

But as the age for the State Pension is rising to 67, people turning 66 in this transitionary period face a longer wait before they are eligible to start claiming their pension - and exactly how long this wait is depends on when your 66th birthday falls.

For those due to turn 66 between June 6 and July 5, you will now become eligible to claim your State Pension when you are 66 years and 3 months old, so you face a three month longer wait before you can get your first payment.

As such, the age increase effectively means losing out on three months worth of State Pension, which under the current rates would amount to £2,895.60 on average for people eligible for the full new State Pension.

As of April 6, the full new State Pension is now worth £241.30 per week, which amounts to £12,547.60 in pension payments over a full year. Split across 12 months, this works out to an average of £1,045.63 per month.

So by having to wait an extra three months before being able to claim the State Pension, people with 66th birthdays between June 6 and July 5 are effectively missing out up to £3,136.89 in pension payments on average due to the age increase, if they're eligible for the full amount.

And those with 66th birthdays later than this will lose even more as the delay for claiming the State Pension increases in monthly increments, meaning some people will be only a month or two away from their 67th birthday by the time they can get their first payment.

According to estimates from the Office for Budget Responsibility (OBR), the move to 67 will save about £10 billion by the end of the decade, compared with keeping the State Pension age at 66.

Explaining the impacts of the State Pension age rise to 67, the Institute for Fiscal Studies (IFS) said: "Previous increases in the State Pension age (SPA) have been shown to cause some people to delay retirement and stay in paid work for longer.

"Employment rates of affected age groups have increased by about 10 percentage points in response to previous increases in the SPA. This effect is fully driven by people staying in their existing jobs for longer, rather than moving to a new job or re-entering paid employment after leaving the labour market.

"However, as only a minority of those affected respond to the reform by working longer, these increases only partially offset the direct loss of income as the SPA is increased.

"Previous research shows that average incomes are markedly lower among affected individuals, as they have to wait longer to receive their state pension.

"Lower household incomes also lead to an increase in income poverty – as the SPA was increased from 65 to 66, the income poverty rate of the affected age group (65-year-olds) rose from 10% to 24%, with the effects concentrated amongst those who were out of paid work."

The DWP has set out the timetable for the graudal increase of the State Pension age to 67, with the process getting under way from April 6. The timetable delays the point at which the State Pension can be claimed in one month increments, so pensioners with a 66th birthday between June 6 and July 5 face an extra three month wait after turning 66 until they can start getting payments.

For example, if you were born on June 6, 1960, then you will become eligible to claim your State Pension on September 6, 2026, when you are exactly 66 years and three months old.

The DWP has confirmed the following timetable for the State Pension age increase to 67, which will affect when people with birthdays between April 6, 1960, and March 5, 1961 can claim their State Pension:

• Born between April 6, 1960, and May 5, 1960 - Reach State Pension age at 66 years and 1 month

• Born between August 6, 1960 – September 5, 1960 - Reach State Pension age at 66 years and 5 months

• Born between September 6, 1960 – October 5, 1960 - Reach State Pension age at 66 years and 6 months

• Born between October 6, 1960 – November 5, 1960 - Reach State Pension age at 66 years and 7 months

• Born between November 6, 1960 – December 5, 1960 - Reach State Pension age at 66 years and 8 months

• Born between December 6, 1960 – January 5, 1961 - Reach State Pension age at 66 years and 9 months

• Born between January 6, 1961 – February 5, 1961 - Reach State Pension age at 66 years and 10 months

Everyone born after April 5, 1977, will get their State Pension at age 67, although a further rise to age 68 is planned between 2044 and 2046.

But the government could bring the age increase to 68 forward earlier than planned as part of a review into the State Pension age announced in July last year, meaning younger generations face an even longer wait to get their first payment.

The review comes amid concerns that adults aren’t saving enough into private pensions for their retirement and will be £800 poorer by 2050.

Announcing the revival of the Pensions Commission last year, Work and Pensions Secretary Liz Kendall said: "People deserve to know that they will have a decent income in retirement – with all the security, dignity and freedom that brings. But the truth is, that is not the reality facing many people, especially if you’re low paid, or self-employed.

"The Pensions Commission laid the groundwork, and now, two decades later, we are reviving it to tackle the barriers that stop too many saving in the first place."