Tom Peterkin: Miliband faces summer of discontent AT A time when our television screens are still recovering from the onslaught of archive footage of Trades Union agitation in the 1970s and 1980s, Ed Miliband is having to deal with some discontent of his own. Coverage of Margaret Thatcher's funeral made much of her efforts to break the unions, but when you are Labour leader they are still very much a power to be reckoned with. Just as Europe - the issue that brought down Thatcher - still divides the Tory party, the tricky relationship between Labour and the trade unions is a constant theme of modern British politics. So this week's attack on the Labour frontbench by Len McCluskey, the outspoken general secretary of Unite, causes all sorts of problems for Miliband, a leader who has yet to convince the electorate that he has what it takes to replace David Cameron. Miliband's problems originate in the contest which saw him defeat his brother David for the Labour leadership. Miliband E only managed to win, thanks to the support of the unions. Perhaps not unreasonably, McCluskey appears to think his organisation has some sort of claim on the Labour leader - an impression that the Conservatives are only too keen to foster. There is also the matter of the £7 million in donations Unite has given to the Labour Party since 2010. It was in an interview with the New Statesman that McCluskey had a go at Miliband's key "Blairite" lieutenants suggesting that their "austerity-lite" economic outlook would fail to capture the imagination of voters. If he is brave enough to go for something radical, he'll be the next prime minister. If he gets seduced by the Jim Murphys and the Douglas Alexanders, then the truth is that he'll be cast into the dustbin of history," McCluskey said. With that remark, one can almost hear the fault line that divides old Labour from Tony Blair's New Labour beginning to wrench open once more. Judging by Miliband's furious response, the Labour leader heard much the same thing. His spokesman was quick to declare that McCluskey was not speaking for the Labour Party and described "this attempt to divide the Labour Party" as "reprehensible." It is the kind of politics that lost Labour many elections in the 1980s, it won't work. It is wrong. It is disloyal to the party that he claims to represent," Miliband's spokesman fumed, evoking Thatcher's domination and Labour's failure in that era. Miliband faces a tough challenge as he heads towards the General Election. How does he deal with restless unions, who may want to drag the party to the left? And how does he persuade the electorate that he is not in thrall to the organisations to whom he owes his job? The unions no longer run the country, but clearly they are still capable of delivering discontent for Labour.