National insurance, voluntary contributions and your pension
Your national insurance contributions affect your pension. If you work for 35 years and pay national insurance, you'll get a full pension. If you miss some years, you can make voluntary contributions - and can do this generally going back six years. You'll normally pay the extra contribution in one go.
In untied Pro, you can choose to make a voluntary contribution if you have a level of income below the minimum where you are required to pay it.