Government says increase in state pension age to 66 will happen in October 2020 – six months later than was planned

Women who would have endured a two-year increase in their state pension age will now wait 18 months instead, following an amendment to the pensions bill.

The work and pensions secretary, Ian Duncan Smith, has announced that the timetable included in the bill currently going through parliament will be changed, with the rise in the state pension age to 66 delayed until October 2020. The increase was previously planned for April 2020.

The move should go some way towards mollifying the 500,000 women born in 1953 and 1954, who previously faced a speeded up increase in their state pension age to 65 by November 2018, followed by a further one-year increase to 66 by April 2020. Some 40,000 faced a two-year delay before they could claim the state pension, compared with their previous expected state pension age.

The previous Labour government had intended to equalise the state pension age for men and women at age 65 by 2020 before raising the age for both to 66 by 2026, but the current government's pensions bill outlined plans to bring forward those changes.

Both men and women will now benefit from the six-month delay.

Duncan Smith: "We have listened to the concerns of those women most affected by the proposed rise in state pension age to 66 and so we will cap the increase to a maximum of 18 months. We have always made clear that we would manage any change fairly and ensure any transition is as smooth as possible."

Campaigners have bombarded ministers, MPs and the media with letters demanding that the decision to speed up a rise in the state pension age be deferred. They argue that the affected women, most of whom are aged 57, need more time to plan their finances or ensure they have work to cover any shortfall in retirement income caused by the later pension payments.

The minister for pensions, Steve Webb, said: "We want to end the uncertainty for women waiting to learn what their State Pension Age is and we will be communicating with those affected so that they can properly plan for their future."

13 October is the last day that amendments could be tabled for the bill. The report stage and third reading of the pensions bill are scheduled for 18 October.

In a statement, the government said it had brought forward the increase in state pension age to 66 because of dramatic increases in life expectancy and the need to ensure that no unfair burden is placed on the next generation. It added that it would spend £45bn extra on pensioners by 2025 because of the triple guarantee to uprate the basic state pension by the highest of earnings, prices or 2.5%.

When the state pension age was set at 65 in1926 there were nine people of working age for every pensioner. There are now three people of working age for every pensioner and that is set to fall to nearer two by the end of this century.

Michelle Mitchell, the charity director of Age UK, said: "We welcome the changes that have been made, they have listened to our concerns and we appreciate that it is a significant financial commitment from the government at a difficult time. This will give a much needed six-month respite to all the women who would have had to work an extra two years.

"We would have liked the changes being made to have gone further. Having faced uncertainty twice already these women must not be affected by any further changes to their state pension age again without sufficient notice."