The leader of Britain's biggest trade union has condemned a decision by Tom Watson to call off a meeting over the leadership crisis as an "act of sabotage."
Len McCluskey, general secretary of Unite, said that a plan to resolve bitter differences in the party had "never been closer", but Mr Watson cancelled the meeting which was due to take place on Sunday.
In a statement Mr McCluskey said: "I am dismayed at the statement issued by Tom Watson announcing his withdrawal from talks aimed at resolving the crisis in the Labour Party.
"When the possibility of a workable plan had never seemed closer, Tom Watson's actions today can only look like an act of sabotage fraught with peril for the future of the Labour Party."
Reforms to tighten rules on trade union strike ballots have passed their first parliamentary hurdle.
The Trade Union Bill was passed by MPs by 33 votes at second reading.
Ministers have defended the Trade Union Bill which would tighten rules on strike ballots in Britain.
MPs debated the proposals for the first time at the bill's second reading in parliament today.
New Labour leader Jeremy Corbyn was present on his party's frontbench for the first time during the debate.
The possibility of a massive strike across the public sector could come closer when a leading trade union reveals the results of a strike ballot today.
The Unite union will announce the result of a vote by its 70,000 members who work in local government in England, Wales and Northern Ireland.
Unison and the GMB have already held ballots with their members voting in favour of industrial action over the Government's decision to limit pay rises to 1%.
Their members will take part in a one-day strike on July 10th, but the participation of Unite members would add to the challenge to the Government's policy of limiting public sector pay rises.
The Labour leader Ed Miliband has said his plans for future leadership contests to be decided by a one member, one vote system "is the right thing to do".
The current electoral college system gives a third of the votes each to the unions, rank and file party members, and the MPs and MEPs.
ITV News Political Correspondent Carl Dinnen reports.
Conservative Party chairman Grant Shapps has called Ed Miliband's plan to to break the historic link between the Labour party and the unions "a complete let down by a weak leader."
"Ed Miliband promised a big change, but absolutely nothing has changed," Mr Shapps said."He is in fact giving the unions even more power to select candidates, to buy the policies of the party," he added.
Labour say this will make their party a mass-membership institution with individual union members choosing to affiliate to the party and having a say in leadership elections - one member one vote - instead of unions acting on their behalf.
There will also be a system or registered supporters, people who are not full members of the Labour Party, who can also then take part in those leadership elections.
But opponents of the Labour party say this would actually give the unions more power because all those affiliated members will actually take up more of the membership block than the unions were getting in the leadership election.
So to an extent, it remains to be seen how this will play out.
Of course this comes because of the Falkirk scandal and the allegations that the party selection process for its next MP up there was rigged and that the Unite union was involved in that.
Nothing was proved there. But Ed Miliband was a beneficiary of this system, whereby the unions have a big say - remember this was the reason he was elected as the party leader, not his brother.
Tories have been using that as a stick to bash him with and he needs to neutralise that threat.
Veteran Labour backbencher Ian Davidson criticised Ed Miliband's plans to break the historic link with the unions, saying the Labour leadership was determined to strengthen its control over the party.
"New Labour have always wanted that because they have always wanted to remove any alternative centre of power. It is going to be a one-way transmission where the line comes down from the centre to individual members," the Glasgow South MP told BBC.
Under the plan, the electoral college system for leadership elections - which gives a third of the votes each to the unions, rank and file party members, and the MPs and MEPs - will be scrapped for a system of one member, one vote.