Steven Cameron, pensions director at Aegon, said: “While government decisions on setting of NI contribution rates may now be taken separately from increases to the state pension, there are still official reports on the position of the ‘NI fund’, showing NI contributions received against payments made year on year.

“The Treasury does have provisions to make special one-off payments from general taxation to prop up the fund. So even if NI contributions are not specifically earmarked, with NI already substantially cut and the potential for it to be scrapped, we need longer term clarity from whoever is in power on where the money for state pensions will come from.”