Those who could benefit are being urged to apply before the 5 April deadline as investing in state pension top-ups can generate a better ‘rate of return’ than almost any other way of using savings.

Someone with 10 missing years could pay a little over £8,000 to fix the gaps but see a boost of £55,000 in state pension over a typical 20-year retirement.

Steve Webb, pension expert at LCP said that ‘under normal rules it is only possible to fill gaps in your NI record up to six years after the year in question. After that point, the year becomes a permanent gap in your NI record and could affect your ability to build up a full state pension. This means that 2016/17 would normally be the oldest year which could be filled in 2022/23’.

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