The constituency was created in the boundary changes of 1918 by merging
Breconshire and
Radnorshire, both previously constituencies in their own right. As part of the
third periodic review of Westminster constituencies there were changes to the boundaries in 1983, when the constituency lost several small areas in the south. While historically having been held by the
Labour Party for forty years, the constituency was captured from the
Conservative government by the
SDP–Liberal Alliance at a dramatic
by-election in 1985. It was regained by the Conservatives in
1992, taken back by the
Liberal Democrats in
1997, and then returned to the Conservatives in
2015. It was the Conservatives' fifteenth target seat at the
2005 election, but the party's share of the vote fell, leaving it as the Conservatives' 95th target seat in
2010, requiring a swing of 5.09%. In the event, the swing to the Conservatives was 0.3%, and the Liberal Democrats retained the seat, with
Roger Williams remaining the MP. In 2015 the seat was reclaimed for the Conservatives by
Chris Davies, whose majority of 5,102 was the largest in the constituency since
Tom Hooson won the seat, also for the Conservatives, in
1983. Roger Williams stood for the Liberal Democrats in 2015 but shed over 6,500 votes from his 2010 result, a loss of 17.8%. In 2019, Davies pleaded guilty to filing false expenses claims, triggering a
recall petition, the third such
petition in the UK. The petition was successful, forcing Davies to vacate the seat. A
by-election was held on 1 August, which was won by Liberal Democrat candidate
Jane Dodds. Dodds was then defeated by Conservative
Fay Jones at the general election in December 2019. ==Members of Parliament==