The Social Welfare Act 1997, in line with the recommendations in the final report of the National Pensions Board, provided for an increase in the number of paid contributions required for entitlement to old age contributory pension from 156 or three years to 520 or ten years. This increase was introduced in two phases with lengthy timescales which recognised the need for a long lead-in time when making fundamental changes to State pension entitlements in order to meet people's expectations and allay fears as much as possible.
There was an increase to 260 paid contributions in the case of a person who reaches pension age on or after 6 April 2002 and an increase to 520 in the case of person who reaches pension age on or after 6 April 2012. The ten years of contributions may comprise an aggregate of 520 qualifying and voluntary contributions of which at least 260 must be qualifying contributions. In addition, a person who was a voluntary contributor on or before 6 April 1997 may qualify on the basis of an aggregate of 520 qualifying or voluntary contributions of which at least 156 must be qualifying contributions.
The Social Welfare Act 1997 was enacted on 2nd April 1997. The increase to 520 contributions was commenced to be effective from a date over 15 years after the legislation introducing it, and this would be considered a reasonable lead-in period for such a change.
I hope this clarifies the matter for the Deputy.