As explained in NIM25001, a person is not entitled to pay (ie, is precluded from paying) Class 3 NICs in certain circumstances. Subject to the qualification in NIM25015, one of those is that they cannot pay for:
Ms D was born on 23rd November 1941. She reached state pension
age (age 60) on 23rd November 2001. For the purposes of calculating
her State Pension entitlement, the final tax year taken into
account was 2000/01.
Up to and including that year, Ms D has only nine qualifying
years. So she is one qualifying year short of the 10 needed to give
her entitlement to the minimum 25% basic State Pension.
The only way she can get the extra qualifying year if she
pays Class 3 NICs for the 2001/02 tax year or any year after that.
But as that tax year is the one in which she was age 60, she is
precluded from paying for that year and any year after it.
For details of the other circumstances in which a person is
precluded from paying Class 3 NICs, see
NIM25006 – NIM25013 and
NIM25015 – NIM25017.