Women born between 6 April 1950 and 5 April 1953 were affected by State Pension age equalisation under the Pensions Act 1995.
The Pensions Act 2011 accelerated the equalisation of State Pension age, and included transitional arrangements limiting State Pension age delays, affecting women born between 6 April 1953 and 5 December 1953. It also brought forward the increase in State Pension age from 65 to 66 which affected women born between 6 December 1953 and 5 April 1960.
Information on the numbers affected by constituent country, parliamentary constituency or local authority is not held by the Department for Work and Pensions. However, the most recent population breakdowns for England and its parliamentary constituencies by age can be found here:
Population breakdowns by local authority can be found here:
The House of Commons library have produced a paper estimating the number of women affected by the Pensions Act 2011 (those born between 6 April 1953 and 5 December 1953) by constituency, which can be found here: