Entitlement to state pension is determined by the number of qualifying years that you achieve during your working lifetime. From 6 April 2010, the number of qualifying years required to receive a full basic pension is 30. Prior to that, it was 44 years for a a male and 39 years for a female.
For the current tax year ending 5 April 2010, you need to have total earnings of at least £4,940 to achieve a qualifying year. (For self-employed indiviudals, a profit of £5,075 is required.) Achieving a qualifying year for state pension also protects your rights to state benefits such as incapacity benefit, even if your earnings fall into the 'lower earnings limit' which is currently between £95 and £100 per week. Employees achieving earnings in that range do not suffer deduction of any National Insurance Contributions from their earnings, but are still credited with a qualifying earnings year.
If you are concerned about the number of qualifying years you have achieved, you should speak to your local TaxAssist Accountant to discuss obtaining a pension forecast. This will allow you to review your position and consider making voluntary contributions if necessary, to ensure that you achieve the full basic state pension.