When Ed Miliband was booed at the TUC in 2011, there was quiet delight among many of his closest aides. They thought that this jeering would help put some distance between Miliband and the unions and show that he wasn’t their puppet despite the role they had played in his election.

But this year, the booing that Miliband is expected to receive will matter far more. Miliband is now engaged in a defining struggle with the union machine over his party reforms. As I say in the Mail on Sunday today, if he doesn’t get them through, then he’ll be a busted flush as a leader.

Unite being cleared by the Labour party of wrongdoing over the Falkirk selection shows just how much of a fight Ed Miliband has on his hand. Falkirk was Miliband’s justification for changing the relationship between Labour and the unions. So if Unite have done nothing wrong in Falkirk, then—at first glance—it appears that Miliband has blundered into a confrontation based on false information. But the truth is more complex than that. One of the reasons that Unite has been cleared is that, rather alarmingly, evidence has been ‘withdrawn’. The whole process makes the case for Miliband’s reforms.

The unions are not going to give in without a fight. Dave Prentis of Unison has been out today rubbishing Miliband’s calls for a special conference to push these reforms through. The GMB has already cut how much it gives Labour and, in a slap to Miliband, made clear that it isn’t going to try and get its members to sign up to Labour directly.

There are now only 21 months until the next election. The last thing Miliband wants is to fighting his party reform battle right up until polling day. But it looks like this is what the unions are going to force him to do. This is a real problem for Miliband as, having staked his political reputation on this fight, he can’t back down.

Tags: Ed Miliband, General Election 2015, Labour, Trade Unions, TUC, UK politics, Unions