Lib Dems Storm to Victory in Streatham – Could Lead to Majority in Southwark

In a groundbreaking result last night, the Liberal Democrats leapfrogged from third to first place to claim victory in the Streatham St Leonard’s by-election in Lambeth.

The seat had been one of the safest Green seats in London, but in just 2 months the Liberal Democrat team created an astonishing 20% swing to claim the seat in convincing fashion.

The result is a landmark victory for the Liberal Democrats in London, proof that the party can win in Inner London in the new multi-party system dominating the politics of 2026.

If the same electoral swing were to take place in neighbouring Southwark, the party would sweep to majority control of the Council.

They would win every seat in the Bermondsey & Old Southwark constituency, and make further gains in North Walworth, Dulwich Village, Goose Green, Dulwich Hill, Dulwich Wood, Old Kent Road, Newington, and Camberwell Green. 

This result would give Southwark Liberal Democrats a majority of councillors in Southwark, with 39 seats out of 63.

Commenting, Councillor Victor Chamberlain, Leader of Southwark Liberal Democrats & Deputy Leader of Southwark said:

“Last night’s amazing result in Lambeth provides proof that Liberal Democrats can win across inner London regardless of previous election results.

“I was proud to visit Streatham yesterday to speak with voters across the area and the message they sent me was clear – the old two-party system of British politics is dead.

“If this incredible result were replicated in Southwark, the Liberal Democrats would win every council seat in Bermondsey & Old Southwark, win the majority of councillors in Southwark, and win for the first time in all parts of the borough.

“The Liberal Democrats are winning across London, and in this new multi-party system, we are the only party who can reliably beat Reform and promote the tolerant, diverse values that make London the best city in the world.”