A by-election was held in the UK Parliament constituency of Newport West in south Wales on 4 April 2019, following the death of Labour Party MP Paul Flynn. Labour nominated the trade unionist Ruth Jones, who held the seat for the party with 40% of the vote and a reduced majority. The Conservative candidate Matthew Evans came second with 31% of the vote, followed by Neil Hamilton, the UKIP candidate, on 8%. This was the third parliamentary by-election held during the 57th UK Parliament, which was elected at the 2017 general election.

Paul Philip Flynn was a British Labour Party politician who served as Member of Parliament (MP) for Newport West from the 1987 general election until his death in 2019. He briefly served as Shadow Secretary of State for Wales and Shadow Leader of the House of Commons in 2016, becoming the oldest MP to hold a Shadow Cabinet position, aged 81.