To achieve a full basic state pension you need to have achieved a certain number of qualifying years. A qualifying year is a year where one of the following applies:
• you have sufficient income to pay National Insurance Contributions
• you are treated as having paid National Insurance Contributions
• you are credited with enough National Insurance Contributions
If you are a man born after the 6th of April 1945 or a woman born after the 6th of April 1950, then you need to achieve a total of 30 qualifying years in order to achieve the full basic state pension.
For tax year 2011/2012, the full basic state pension will be GBP102.15 per week. This will increase annually by the highest of prices, earnings or 2.5 per cent (If you live in certain countries, then your pension will not increase when you start drawing it. Find out which countries are affected here).
If you have less than 30 qualifying years, your pension will be reduced on a pro rata basis. E.g. if you only had 15 years, you would get GBP51.08 per week (15/30 = 50% of GBP102.15).