Jane Dodds, the Lib Dems‘ leader in Wales, won with 43.5% of the vote, ahead of former Tory MP Chris Davies on 39% after he triggered the by-election following his conviction for submitting false expenses.
Polls have closed in the Brecon and Radnorshire by-election as new prime minister Boris Johnson faces his first test at the ballot box.
Polls have now opened in the Brecon and Radnorshire by-election.
The 93 polling stations in the constituency are open until 10pm tonight.
Mr Davies was fined £1,500 and ordered to pay £2,500 towards legal costs, whilst also forced to carry out 50 hours of community service.
He was again chosen by the Tories to fight for the crucial Parliamentary seat after more than 10,000 constituents signed a petition to remove him.