Royal London is urging those helping with their family’s childcare to claim this additional benefit after it discovered only one in ten of those entitled were currently taking advantage.
It said, by taking up their entitlement, a grandparent caring for a grandchild for one year could increase their state pension by around £230 a year.
Over a 20-year retirement that could amount to more than £4,500.
Steve Webb, director of policy at Royal London, said: “It is right and proper that when grandparents sacrifice their own working life to help a family member get back to work, they should not also damage their own state pension prospects.”
Royal London discovered last year only 1,298 people had claimed the National Insurance credit between October 2015 and September 2016. Its publicity of the poor-take up prompted a surge in interest.
Now it has obtained new data under the Freedom of Information Act and discovered, since its initial publicity, there had been a seven-fold increase in grandparents claiming.
But, it said, many more had yet to claim and estimated only one in ten of those entitled had applied to receive the credit.
Webb added: “It is good news that the numbers claiming have risen so dramatically in such a short space of time. But we believe there are tens of thousands more grandparents who could be entitled to benefit and would encourage them to find out more about the scheme and make a claim.”
Under the system, the person receiving child benefit – usually the mother – signs over their National Insurance credit to the grandparent.