THE boss of the Unite trade union yesterday said there was a "moral justification" to Labour overhauling its funding relationship with the unions in the wake of the Falkirk vote-fixing scandal.

Speaking directly for the first time about Labour leader Ed Miliband's proposal to end the automatic affiliation fee some union members pay the party, Unite general secretary Len McCluskey said he was enthusiastic about the idea, but warned that the move, which could cost Labour £5 million a year, was a "gamble".

The comments appeared to signal an end to McCluskey's furious public row with Miliband following the suspension of the Westminster candidate selection process in Falkirk amid claims of a Unite "stitch-up".

Labour's biggest donor was accused of trying to pack the local party with its members to ensure Karie Murphy was chosen as Labour's replacement for disgraced MP Eric Joyce at the 2015 General Election.

An internal Labour investigation found that some Unite members were signed up to the party without their consent. After David Cameron accused him of being too weak to stand up to his union funders, Miliband announced the end of the automatic levy, with people only paying "deliberately" in future.

Speaking at the annual Durham Miners' Gala, McCluskey told the BBC: "At the moment Unite affiliates one million of our members who pay our political levy to Labour.

"Ed has said, 'I don't think that's right, I think it should be people who want to be associated with Labour'.

"And I have to say I think there's some moral justification for that."

McCluskey said he was ready for reform, but was unrepentant about Unite's broader aim of more working-class MPs.

"The Labour party must understand it can only exist if it remains the voice of ordinary working people," he said.

"The parliamentary Labour party today does not look like, or think like, the working-class communities it seeks to represent.

"That is what Unite was fighting for in Falkirk: to give the working class a stake in our democracy. I make no apology for that."

After Falkirk, Miliband said he wanted an end to "machine politics", and one of the party's first tests could soon be a potential Holyrood by-election in Dunfermline, where two Labour clans are poised to slug it out over a plum candidacy.

With independent MSP Bill Walker on trial accused of multiple assaults against his ex-wives – allegations first reported in the Sunday Herald, which Walker denies – all parties are on alert for the potential of a by-election should there be a guilty verdict.

A former Labour bastion, Walker won Dunfermline for the SNP in 2011 by just 590 votes. Labour need only a 1% swing to regain it.

However, a by-election could expose the party to fresh claims of cronyism. The two frontrunners for the candidacy in the event of a by-election are both daughters of Labour MSPs, with strong union links.

Cara Hilton, 37, is the daughter of former Falkirk East MSP Cathy Peattie. Once a researcher for the shopworkers' union Usdaw, she was elected councillor for the Fife ward of Dunfermline South last May, and is an assistant to Dunfermline MP Thomas Docherty.

Fiona Yates, 42, is part of a Labour dynasty. Her mother is Cowdenbeath MSP Helen Eadie, her father Bob Eadie was a long-serving Fife councillor, her late grandfather Alex Eadie was MP for Midlothian, and her husband is Kirkcaldy & Cowdenbeath councillor, Gavin Yates.

A solicitor, she is a secretary of the civil service union, the First Division Association.

Also tipped as a potential candidate is Fife councillor Lesley Laird, whose father was the former STUC chairman, John Langan.

Former Lothians MSP Shirley-Anne Somerville is tipped to stand for the SNP in any by-election.

Walker, 71, who was expelled from the SNP last year, denies a breach of the peace and 23 charges of assault against three former wives and a stepdaughter between 1967 and 1995. His trial began at Edinburgh Sheriff Court last Monday, and was adjourned on Friday to July 29.

As the case is a summary one, meaning there is no jury, the maximum sentence the sheriff can impose is 12 months.

A person is disqualified from parliament only if sentenced to "more than a year". However, a guilty verdict would inevitably lead to calls for Walker to resign. An SNP source said the party wants a by-election but does not expect one.

Labour said: "In the event of a by-election in Dunfermline, members of our local party will be given the chance to select the best possible candidate to represent their community."

Hilton and Yates did not return Sunday Herald calls.