Cambridgeshire: Des Watt, who was elected for Reform UK in Yaxley and Farcet division but had left them and joined Advance UK in January, has now left Advance UK and is once again a non-aligned Independent county councillor.
Chelmsford: Jacob Armstrong, who was elected for the Conservatives in Little Baddow, Danbury and Sandon ward, has joined Reform UK.
East Suffolk: Amanda Folley, who was elected for the Labour Party in Western Felixstowe ward, has left the party to sit as an Independent councillor.
Fife: Stefan Hoggan, who was elected for the Scottish National Party in Cupar ward, has left the party to sit as an Independent councillor.
Kent: Bill Barrett, who was elected for Reform UK in Ashford Rural South division but left the party in October, has now joined the Conservatives (from whom he defected before the 2025 elections).
Manchester: Muqaddasah Bano, who was elected for the Labour Party in Whalley Range ward but was suspended from the party last July, has now returned to the Labour whip.
Newark and Sherwood: Rowan Cozens, who was elected as an Independent in Beacon ward and had been in the Independents for Newark and District group, has joined the Labour Party.
North Kesteven: Nikki Dillon, who was elected as an Independent but joined Reform UK in May last year, has now left Reform UK to sit as an unaligned councillor.
Redditch: Matt Dormer, who was elected for the Conservatives in Webheath and Callow Hill ward, has left the party to sit as an Independent councillor.
Tewkesbury: Mary Jordan, who was elected for the Liberal Democrats in Churchdown St John’s ward, has left the party to sit as an non-aligned councillor.
Wolverhampton: Wendy Dalton, who was elected for the Conservatives in Merry Hill ward, has left the party to sit as an Independent councillor.
New vacancies
Aberdeen: George Street / Harbour ward, after the resignation (effective on 2 April) of Liberal Democrat councillor Desmond Buchanan. Term ends 2027. His resignation will mean the SNP / Liberal Democrat administration loses an overall majority.
Chesterfield: Staveley North ward, after the death of Liberal Democrat councillor Paul Jacobs. Term ends 2027.
Dorset: Bridport division, after the death of Liberal Democrat councillor Dave Bolwell. Term ends 2029.
Guildford: Onslow ward, after the resignation of Liberal Democrat councillor James Jones. Term ends 2027.
Halton: Farnworth ward, after the resignation of Labour councillor Valerie Hill. She would have been up for re-election in May so no byelection follows.
Hertfordshire: Flamstead End and Turnford division, after the resignation of Reform UK councillor Tony Hill. Term ends 2029.
Hounslow: Hounslow East ward, after the death of Labour councillor Junue Meah. His term was due to end in May so no byelection will be held.
Kirklees: Lindley ward, after the death of Independent councillor Cahal Burke, who was elected as a Liberal Democrat. His term would have ended in May so he will not be replaced in a byelection.
Leeds: Temple Newsam ward, after the resignation of Labour councillor Nicole Lloyd. Term ends 2027.
Reigate and Banstead: Earlswood and Whitebushes ward, after the resignation of Green Party councillor Ruth Ritter. Term ends 2027.
Dates for byelections
Leicestershire: The byelection due in Narborough and Whetstone division will be held on 16 April.
Surrey: The byelection due in Warlingham division will be held on 7 May.