Fourth periodic review of Westminster constituencies
The fourth periodic review of Westminster constituencies was undertaken in the United Kingdom between 1991 and 1995 by the four boundary commissions. As well as changes to constituency boundaries, the reviews recommended an increase of five seats in England (524 to 529), two in Wales (38 to 40) and one in Northern Ireland (17 to 18), with Scotland continuing to have 72 seats.
Source: Wikipedia — Fourth periodic review of Westminster constituencies (CC BY-SA 4.0)