By-election voters go to polls in Cardiff, Corby and Manchester
Voters are turning out for three parliamentary by-elections, following the resignations of one Conservative and two Labour MPs.
The seats which are being contested are Cardiff South and Penarth, Corby and Manchester Central.
Polls opened at 07:00 GMT and close at 22:00 GMT, with the weather expected to be fairly dry, but chilly, in each.
Meanwhile, voters in Bristol are choosing a directly-elected mayor for the first time.
The by-elections in Cardiff South and Penarth and Manchester Central follow the resignation of the sitting MPs, Labour's Alun Michael and Tony Lloyd, to run for election as police and crime commissioners.
The contest in Corby, Northamptonshire, comes after Conservative MP Louise Mensch quit to move with her family to New York.
Fourteen candidates are standing in Corby, 12 in Manchester Central and eight in Cardiff South and Penarth.
The ballots in Manchester and Cardiff will be counted from the close of polls, while those in Corby will not be checked until Friday.
The election of a mayor in Bristol follows a referendum earlier this year, in which voters chose to move to this system. Fifteen candidates are taking part.