Labour has won a crucial local by-election in Wandsworth as the borough faces imposing the country’s largest ever council tax increases.

The Conservatives piled on pressure to turn out Tory voters in the Trinity Ward poll on Thursday, including personal campaigning by leader Kemi Badenoch and shadow cabinet members.

But, while the Tories were able to increase their vote share by nine percentage points, Labour’s also went up by almost the same amount.

The Green Party’s vote share dropped by over 10% with Labour seemingly the major winners.

Shirin Georgiani was declared the new councillor for the ward in the early hours of Friday morning.

At the most recent polls, in May, the Tories secured 29 seats on the council, placing the party one short of the 30 required for a majority.

Labour has 28 councillors. But Lizzy Dobres, who represented Trinity ward for the party, quit her role shortly after the election to take up a new job that is "politically restricted".

The result means the Conservatives remain the largest party on the council, but only by a single seat.

Wandsworth is among the five London town halls that face having to impose the largest council hikes ever seen and is planning to launch a legal process challenging the Government’s decision to slash their funding.

Wandsworth, Kensington and Chelsea and Westminster councils are expected to officially appeal the significant cuts.

Under the Government’s Fairer Funding Review the three Tory-led councils, along with Labour-led Hammersmith and Fulham, the City of London and Windsor and Maidenhead, will see the largest cuts to funding settlements.

The six town halls are exempt from the cap on raising council tax, set at 5%, from next year, which means residents’ payments will need to rise well above the national maximum to make up shortfalls.

Wandsworth is understood to be proposing increasing bills by as much as 160% as it faces losing £84 million a year in funding by 2030.

Westminster has warned it will have to hike bills by up to 200% unless significant cuts are made to services.

Leaders of the three boroughs met with shadow local government minister Sir James Cleverly and Tory party chairman Kevin Hollinrake on Wednesday to discuss challenging the new settlements.

An official announcement is expected to come today.

Wandsworth Labour leader Simon Hogg said the Trinity ward result showed “voters are clear: the Tories need to scrap their plans to double council tax”.