Ed Miliband hit back at a senior trade union leader - saying he was "wrong" to oppose a public sector pay freeze and insisting Labour under his leadership would be "the party of the private sector" as much as the public.
The Labour leader sought to use the row with Len McCluskey - general secretary of Labour's biggest union donor Unite - to show that the movement is not "pulling our strings".
He issued a strongly-worded put-down as the party gathered for its autumn conference in Manchester, two years on from Mr Miliband's surprise leadership election victory in the city with the help of union votes.
Mr McCluskey used an eve-of-conference interview with the Sunday Times to set out his plans to "kick the New Labour cuckoos out of our nest" and win back the party for the trade union movement.
And he warned that his members were "furious" with the Labour leadership's "crazy" policy of supporting pay restraint.
Mr Miliband, who is battling to improve personal poll ratings and shake off his "Red Ed" tag, told BBC1's Andrew Marr Show: "It's not going very well for him is it?
"You can't say at one and the same time that Len McCluskey is saying 'you're wrong on pay restraint' and then say we're giving in to him and he is pulling our strings."
Asked about the pay freeze, he said: "He is entitled to his view but he is wrong.
"We've got the right policy to say we put jobs in the public sector ahead of pay rises. That's what we said we would do this parliament. It is a difficult decision but it is the way to keep jobs in the public sector."
Mr McCluskey told the newspaper: "We should only be supporting those constituencies where their vision of the type of future that we want is in line with ours."