Over time, should National Insurance contributions be increased to fund a lowering of the retirement age?

The UK state pension age is rising to 67 by 2028 and has been brought forward to 68 from the 2040s. National Insurance contributions from current workers fund today's pensioners in a pay-as-you-go system under strain from longer lifespans and a higher old-age dependency ratio. Lowering the retirement age would increase the number of claimants while shrinking the contributing workforce, requiring higher NI rates or alternative funding.