The Conservatives have lost London stronghold Wandsworth for the first time since 1978. The totemic seat was once Margaret Thatcher's favourite council and, until Friday morning, had been controlled by the Tories since 1978.

Keir Starmer's party won 35 out of 58 seats – taking nine seats from the Tories. Wandsworth was a key symbolic target for Labour in the local elections – one of the last remaining high-profile Tory strongholds in the capital. Labour now holds 35 seats on the council while the Tories hold 22 and the Independents one.

Forecasters predicted Labour would win the borough as it became a battleground for the two main parties over its famously low council tax versus anger over the Downing Street "partygate" scandals and frustration with local services. The outcome is thought to be a key indicator of public mood on the main parties.

Wandsworth Labour leader Simon Hogg had predicted the results would be tight – coming down to a few dozen votes in key wards. He said after the results were announced that he had thought Labour's chances were 50/50 ahead of tonight, but that the results "exceeded" the party's expectations.

He told the Local Democracy Reporting Service: "It feels fantastic. It's been a really good evening and something I've been working towards for 20 years." He added that the newly-elected Labour councillors were "ready to get to work in the morning".

He said Labour's "positive vision" for Wandsworth alongside the national picture – the cost of living crisis and anger over "partygate" – led to Labour's victory in the borough.

Labour sources seemed optimistic about a victory from the start of the night. One Labour candidate said the party was "confident but not complacent" and that people were "disgusted with the behaviour of the prime minister, particularly in respect of Partygate" on the doorstep.

An organiser for Wandsworth Labour said: "We're all over the moon because we're winning seats that we didn't even conceive of being possible. It's so exciting to think there's going to be change in Wandsworth after more than 40 years."

Council tax, "partygate" and local social care services emerged as the key issues for Londoners ahead of the local elections. Wandsworth became the only London borough to cut council tax this year, and also froze rent for council tenants, heating and hot water charges. The party's 44-year control of the borough has seen it at the forefront of Thatcher's Right to Buy scheme and the privatisation of local services. It also briefly set poll tax at zero in the 1990s.

Labour based its manifesto this year on keeping the same low council tax in the borough while providing "better public services". It has promised to build 1,000 new council homes, set a target of 50 per cent affordable housing on all new developments and pay all council workers the London Living Wage.

The two main parties battled it out alongside a considerable number of Liberal Democrat and Green candidates. The Trade Unionist and Socialist Coalition Party, Labour and Co-operative Party and some Independents also ran in some of the wards.

Labour's victory comes after a tight race for control between both parties in 2018, when Labour took seven seats from the Tories. Labour also won the popular vote that year while locals elected three Labour MPs in the general election in 2019. This included Fleur Anderson in Putney, who took the only seat from the Tories in the general election.

The hotly-contested by-election in November for the council's Bedford ward seat indicated Thursday's result would come down to the wire. Labour won the seat by just one vote after the resignation of Independent ex-Labour councillor Hannah Stanislaus in August 2021.

Labour now has 35 seats on the council, while the Tories have 22 and the Independents have one following the announcement of the final election results at around 4.30am on Friday morning. Boundary changes mean the overall number of seats on the council has fallen from 60 to 58.

In the newly-created Wandle ward, locals voted in two Labour councillors. Former Tory MP Adrian Flook was standing for election in the new ward but lost out by 233 votes. Tory leader Ravi Govindia held his seat in East Putney by just 32 more votes than winning Labour candidate Finna Ayres.

Other wards won by Labour include Trinity, South Balham and Battersea Park.