Hundreds of thousands of women could be owed money back from the Department for Work and Pensions (DWP) due to historic state pension underpayments.

More than 230,000 people, mainly women, are thought to have been underpaid their state pension. Those who have potentially been underpaid include married women and widows who hit state pension age before April 2016. Those aged 80 and over - regardless of whether they're married or not - may also be owed cash.

The latest figures from the DWP show 21,175 widowed women were underpaid their state pension and have received £12,486 on average back. Meanwhile, 32,474 over 80s have received £2,192 on average and 43,367 married pensioners got £5,713.

The DWP estimates around £835million is owed to pensioners in total. We've run through the key groups of people who could be owed money back, plus higher state pension payments going forward. An online tool launched by former pensions minister Sir Steve Webb on behalf of actuarial firm LCP can also help you identify if you might have been affected.

Married women

Married women who reached state pension age before April 2016 should have seen their payments boosted to 60% of their husband's basic state pension entitlement. The basic state pension for 2024/25 is worth a maximum of £169.50 a week. If he turned 65 after March 17, 2008, you should get automatic top-ups if you've been underpaid.

It may be possible to backdate your payments to your husband's 65th birthday, or to when you reached state pension age. If your husband turned 65 before March 17, 2008, then you'll need to claim any money owed - you won't receive any payments automatically. You can only get backdated payments going back 12 months, however, some women are trying to challenge this through the Parliamentary Ombudsman.

Widowed women

Some widows did not see their state pension increase when their husband died, based on his contributions. You may also be able to inherit up to 100% of his additional state pension, also known as SERPS. If you are due money back, this will be backdated to when your husband died.

If you're a widow, it may also be possible that you were underpaid while your husband was still alive and you received less than 60% of his basic state pension entitlement. Your claim should now be automatic if your husband died after March 17, 2008, and it can backdated to your husband's 65th birthday, or when you hit state pension age.

Divorced women

Divorced woman on a small state pension may also have been underpaid. This is because a change in the rules means you can substitute your National Insurance record of your ex-husband for your own, up to the date of your divorce. This could potentially boost your pension up to the maximum basic allowance, currently £169.50 a week.

If you divorced your husband after you reached state pension age, you'll need to make a claim, as any top-ups won't be automatic. Women who got divorced before reaching state pension age should have seen their payments automatically increased.

Over-80s

If you're aged over 80 and get a state pension of less than £85 a week, regardless of whether you're married, widowed, divorced or single, you may also have been underpaid. These people should have automatically been entitled to a "category D" state pension when they turned 80.

To qualify, you must have been living in the UK, Channel Islands, Isle of Man, a European Economic Area country or Switzerland on your 80th birthday. You must also have lived in England, Scotland or Wales for at least 10 years in any 20-year period after your 60th birthday.

Any back payments should be automatic, unless you're not already getting any state pension at all, in which case you would need to claim.