The polls have opened in three by-elections where defeats would heighten Conservative fears that Rishi Sunak will struggle to lead them to another Commons majority.
The seats of Uxbridge and South Ruislip in west London, Selby and Ainsty in North Yorkshire, and Somerton and Frome in Somerset, are all up for grabs, with polls closing at 10pm.
Results are expected in the early hours of Friday.
The Prime Minister braced MPs at a meeting of the 1922 Committee of Tory backbenchers on the eve of the polls that they face a “tough battle”.
The three seats were left empty by outgoing Conservative MPs - former prime minister Boris Johnson and Nigel Adams - and former Tory David Warburton.
Constituents will need photo ID in order to vote.
There are 17 candidates in Uxbridge and South Ruislip:
- Blaise Baquiche, Liberal Democrat
- Danny Beales, Labour
- Cameron Bell, Independent
- Count Binface, Count Binface Party
- Piers Corbyn, Let London Live
- Laurence Fox, Reclaim Party
- Steve Gardner, Social Democratic Party
- Ed Gemmell, Climate Party
- Sarah Green, Green Party
- Kingsley Hamilton, Independent
- Richard Hewison, Rejoin EU
- Howling Hope, Official Monster Raving Loony Party
- 77 Joseph, Independent
- Rebecca Jane, UKIP
- Enomfon Ntefon, Christian Peoples Alliance
- Leo Phaure, Independent
- Steve Tuckwell, Conservative Party
There are 13 candidates in Selby and Ainsty:
- Andrew Gray, Independent
- Claire Holmes, Conservative Party
- Mike Jordan, Yorkshire Party
- Dave Kent, Reform UK
- Keir Mather, Labour Party
- Nick Palmer, Independent
- Guy Phoenix, Heritage Party
- Sir Archibald Stanton, The Official Monster Raving Loony Party
- Matt Walker, Liberal Democrats
- Arnold Warneken, Green Party
- John Waterston, Social Democratic Party
- Luke Wellock, Climate Party
- Tyler Wilson-Kerr, Independent
And there are eight candidates in Somerton and Frome:
- Lorna Corke, Christian Peoples Alliance
- Martin Dimery, Green Party
- Sarah Dyke, Liberal Democrat Party
- Bruce Evans, Reform UK
- Neil Guild, Labour Party
- Rosie Mitchell, Independent
- Faye Purbrick, Conservative Party
- Peter Richardson, UKIP
