Labour’s biggest union donor held secret talks this week with Reform UK in anticipation of Nigel Farage’s party taking control of Europe’s biggest local authority.

In their first direct engagement with Reform’s leadership, officials from the Unite trade union met senior advisers to Farage in Birmingham on Tuesday.

The “constructive” discussions focused on how the party might resolve the city’s year-long bin strike if it wins control of the council in next month’s local elections.

Nigel Farage speaking at a Reform UK press conference.Nigel Farage on MondayJames Manning/PA

An opinion poll this week suggested that Reform is set to come a strong second in Birmingham, run by Labour since 2012. The council has been hit by repeated scandals and effective bankruptcy in recent years.

Unite — whose leader, Sharon Graham, is openly considering disaffiliation from the Labour Party — is seeking support from all political parties in the city for its demands to end the strike.

The union’s decision to meet Farage’s representatives will nonetheless be seen as provocative by the government. The meeting was not publicised and took place in a Holiday Inn on the outskirts of the city.

General Secretary of Unite the Union Sharon Graham marching with demonstrators against the far right.Sharon GrahamWiktor Szymanowicz/Future Publishing/Getty Images

Unlike other parties, Labour did not respond to a request to commit to a new round of negotiations or the publication of the council’s legal advice on the strike. This advice followed the council’s decision to make refuse workers redundant to comply with a court ruling on equal pay for female employees.

Graham, who said last September she would “talk to the devil himself if it meant … a better deal for workers”, was not present.

A spokesman for Reform said its “administration in Birmingham will rapidly get round the table with Unite to agree a solution” if elected next month.

Sources close to Farage hailed the meeting, one of several Unite has held with rival parties to Labour, as a significant step in his efforts to loosen Labour’s grip on its traditional base.

He has repeatedly stressed he wants a “sensible relationship” with trade unions and has insisted his politics are no longer Thatcherite. Last year he was pictured alongside unionised steelworkers in Scunthorpe.

Reform’s commitment to reach a settlement with Unite if it wins in Birmingham — where Labour’s historic coalition is also under serious threat from the Greens and Gaza independents — is nonetheless its most significant attempt so far to build bridges with the unions.

Piles of black rubbish bags overflowing onto a street in a Birmingham neighborhood due to a refuse collector strike.Reform say if they are elected in Birmingham, “we will resolve the bin strike and end the absurd waste of millions of pounds on agency staff”Jack hill for the sunday times

Endorsing most of the union’s key demands, a party spokesman said: “The council has wasted £34 million already on this dispute.

“They have argued about the legal risks involved, but while Unite have published their legal advice on equal pay, the council has not produced any evidence or provided documents to back up their arguments.

“We call on the council to be transparent and share its legal advice now. This is vital to enable a new Reform UK administration to hit the ground running and get this settled in May.”

The spokesman added: “If Reform UK are elected in Birmingham, we will resolve the bin strike and end the absurd waste of millions of pounds on agency staff by prioritising more appropriate, stable, permanent jobs that offer better conditions for staff and better value for taxpayers.”

A survey by More in Common this week found the party would win 26 Birmingham councillors to Labour’s 32 if an election were held tomorrow, pushing the Conservatives into third and tipping the council into no overall control.