The state pension age for women has increased to 65, as of 6 November 2018.
This change means women now qualify for their state pension at the same age as men, after decades of different treatment.
The pension age for women has been rising gradually from 60 to 65 since 2010, under legislation passed in 1995.
These increases were then accelerated by new measures in 2011, and the state pension age for both men and women will now continue to rise, to 66 by October 2020 and 67 by 2028.
Critics have argued that the changes have been made too quickly, and that other inequalities in the pensions system mean women lose out compared to men.
Former pensions minister Ros Altmann said that while state pension ages are now the same, "equal state pension age does not mean pension equality".
Altmann said women typically have lower pensions than men, placing them at risk of financial difficulty in retirement - especially as they also tend to live longer.
"Some of the [pension] inequalities date back many decades, but others are new problems created by recent legislation.
"The Government needs to act urgently to fix these loopholes which cause problems for so many women."
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