Who's up and who's down?
Thursday 18 December marked the final council by-elections in 2025. More by-elections are scheduled, but all of these will now take place in 2026.
Election Maps UK keeps a running tally of the results of all council by-elections. According to their records, there are a number of pretty clear trends since the local elections which took place in May 2025.
Reform have won 68 council seats in by-elections since May, and 58 net gains. A gain is classified as an instance where the winning party did not hold the seat prior to the election and instead won it from another party. Reform are way out in the lead when it comes to gains.
But the Liberal Democrats have also had a very good showing. They’ve won 56 seats since may, with 19 net gains.
The only other party to have made net gains in by-elections since May 2025 is the Greens. Their success is much more modest, with two net gains in total.
Things are a lot less positive for Labour and the Tories. Labour have suffered net losses of 44 seats since May. The Tories, meanwhile, stand on 23 net losses.
Despite this, Labour remains by far the largest party in local government in the UK. Keir Starmer’s party has more than 6,000 councillors across the country.
The Tories have more than 4,000 councillors, the Lib Dems more than 3,000. Both Reform and the Greens have less than 1,000 each.
Chris Jarvis is head of strategy and development at Left Foot Forward
Left Foot Forward doesn't have the backing of big business or billionaires. We rely on the kind and generous support of ordinary people like you.
You can support hard-hitting journalism that holds the right to account, provides a forum for debate among progressives, and covers the stories the rest of the media ignore. Donate today.