The fourth periodic review of Westminster constituencies was undertaken in the United Kingdom between 1991 and 1995 by the four boundary commissions.
Under the terms of the Parliamentary Constituencies Act 1986, as enacted, the boundary commissions were required to present their final recommendations between 10 and 15 years after the submission of their previous reports.
[4] The final reports were submitted as follows: As a result of changes to the names of seats, it is not always easy to clearly identify newly created constituencies or those abolished during the review process.
There are a number of instances where existing seats are effectively abolished and re-created under the same name, as set out in the notes.
The number of seats in Northern Ireland was increased from 17 to 18 through the creation of West Tyrone.
This comprised the majority of the existing Mid Ulster seat, which was reconfigured and effectively formed a new constituency.