The proportion of women set to receive the full basic state pension is set to nearly double in 20 years time, the Office for National Statistics (ONS) said today.
Its latest Pension Trends report found that in September 2010
fewer than half (48%) of female pensioners received a full basic
state pension (BSP), compared with 87% of male pensioners.
Many women in the current generation of pensioners failed to build up full or near-full BSP entitlement under a previous system in place before April 2010, mainly because of broken work histories and part-time work patterns, the ONS said.
However following changes to the law, 95% of women reaching state pension age (SPA) in Britain in 2030/31 are expected to receive a full BSP.
The Pensions Act 2007 changed the rules on building up entitlements to the BSP, including cutting the number of years needed to qualify for the full pension.
The "purchasing power" of the BSP is also forecast to rise, the ONS said, following the Pensions Act which re-linked state pension increases to earnings.
In 2010 the Government introduced the "triple lock" policy, guaranteeing that BSP will be increased each year by average earnings growth, inflation or 2.5%, whichever is higher.
Forecasts by the Department for Work and Pensions (DWP) suggest that by 2030 the purchasing power of the BSP would increase by almost half.
However it is also suggested that 60% of the female baby boomers reaching state pension age between 2016 to 20 will have entitlements of less than £140 per week in 2011/12 earnings terms, the ONS said.
ONS head of pensions analysis Sarah Levy said: "In the long run things look set to improve in the number of women receiving basic state pensions.
"The legislative changes come in gradually and we have still got a large number of people who retired under the old system."
Earlier this month, the Government announced changes to the planned increase in the state pension age, saying that tens of thousands of women would benefit at a cost of more than £1 billion.
The DWP said a plan to raise the state pension age to 66 in 2020 would be delayed by six months from April 2020 to October 2020.
Around 245,000 women and 240,000 men would benefit, including 33,000 women who would have experienced a two-year rise in their state pension age, the Government said.
However unions said the move gave "precious little comfort" to women, while experts warned women's pensions plans would be thrown into disarray.
Pensioners have been lobbying Parliament for increased rights in retirement, including a higher state pension.
The National Pensioners Convention (NPC) is pressing for changes including a National Care Service, paid for through general taxation, and a winter fuel allowance of £500 per pensioner household to help old people pay rising energy bills.
The NPC has said Britain's state pension was among the least adequate in Europe, and sixth from bottom out of the world's 46 most developed countries.
The ONS today also released its Occupational Pension Schemes Survey for 2010, which found that active employee membership of such schemes is on a slide to levels not been seen for half a century.
The highest number of active members was recorded in 1967, when there were 12.2 million.
But by last year there were 8.3 million active members - the lowest level since the 1950s, the ONS said.
Since 2004, public sector active membership has overtaken private sector active membership as numbers in the private sector have fallen sharply.
In 2010, almost two-thirds of active members were in the public sector, the ONS found.
Average contribution rates in the private sector in 2010 were lower in defined contribution schemes than in defined benefit schemes.
Defined benefit occupational pension schemes are those in which the rules specify the rate of benefits to be paid. The most common such schemes are "final salary", but "career average" schemes are on the increase.
Defined contribution schemes, also known as money purchase schemes, are ones where the benefits are determined by the contributions paid in and the investment return.
The average employee in a defined benefit scheme contributed 5.1% of their salary (excluding bonuses) to their pension, compared with 2.7% in defined contribution schemes.
Typical employer contribution rates were 15.8% in defined benefit schemes and 6.2% in defined contribution schemes.
Unison said the figures revealed that not enough people are saving for their later years - storing up a "huge benefits timebomb" for the taxpayer.
General secretary Dave Prentis said: "This survey shows just how few private sector workers are saving for their retirement.
"But for top bosses in the private sector, it is a different story. They award themselves generous pensions with low retirement ages, but shut their schemes to staff - leaving them facing poverty in their later years, with the only lifeline means-tested benefits.
"Even though this will cost taxpayers billions, it is used to attack pensions rights in the public sector."
He added: "What our country really needs is a decent pensions deal for all workers.
"Unison is campaigning for the pensions rights of people in the public and private sector - all workers should be able to save for dignity in their retirement."
Minister for Pensions Steve Webb said: "It will be decades before women see equal outcomes to men in their basic state pension and state second pension.
"This is why reform is so crucial. A flat rate pension set above the level of the basic means test - currently around £140 - would reduce the need for means testing and would ensure that women are no longer penalised for taking time off work to care for their families."
Joanne Segars, chief executive of the National Association of Pension Funds, said: "People are thinking about today and putting tomorrow on hold, and unfortunately saving into a pension is being seen as a luxury.
"The exodus is especially noticeable in the private sector, where confidence in pensions is running at a record low.
"People are being put off by stock market turmoil, falling annuities, and mistrust of the pensions industry's fees and charges.
"While it's understandable that spending gets prioritised during difficult times, it's essential that people don't forget about their retirement. The UK is on a collision course with its own old age."
She added: "Landmark reforms to auto-enrol all workers into a pension from next year will make a big difference.
"Five to nine million people are set to save into a pension for the first time, or to save more."
TUC general secretary Brendan Barber said: "The shocking decline in private sector occupational pensions shows the folly of calls for public sector pensions to be equalised with those in the private sector. This would simply be a race to a very grim bottom.
"Making public sector pensions more like those in the private sector would mean taking pensions away from most women and low- paid workers in the public sector, while giving top public sector staff the boardroom bonanza pensions enjoyed in the private sector."