Firstly, we are talking about the old style Basic State Pension (before April 2016) and not the New State Pension (after April 2016).
Some divorced women being paid a basic state pension may be entitled to claim more. If you answer yes to all of the following:
Up to April 1977, married women could choose to pay a reduced rate of National Insurance sometimes called the 'small stamp’ or ‘married woman’s stamp’. Did you pay this?
You reached state pension age and claimed state pension before April 2016 i.e. you are still on the old style basic state pension system.
Still Married At State Pension Age But Since Divorced:
If you were still married when you claimed your state pension, if you did not have enough years of national insurance credits, you would have received the ‘Married Woman’s Rate’, currently £80.45 per week.
If you have since divorced and your husband had a full national insurance record, you are actually entitled to claim a full basic state pension (currently £134.25 per week) but you must contact the Department for Work and Pensions to update them and claim the full basic state pension. They will not automatically contact you.
Already Divorced When Reached State Pension Age
If you were already divorced and had not remarried when you reached state pension age and your ex-husband had a full national insurance record, the DWP would have automatically adjusted your own basic state pension entitlement.
If in doubt, contact the Department for Work and Pensions: https://www.gov.uk/browse/working/state-pension