He accused Ed Balls of grasping for 'discredited Blairism' over Labour's core values. So how does he see the party's politics?
Outside the shadow cabinet there are few people more important in Labour politics than Len McCluskey, the general secretary of Unite, Britain's biggest union and Labour's biggest donor. I'm interviewing him tomorrow. What do you want me to ask?
McCluskey caused a stir last month when he wrote an article for the Guardian saying Ed Balls' refusal to promise to reverse spending cuts in 2015 was "a victory for discredited Blairism at the expense of the party's core supporters". It will be worth exploring this, as well as McCluskey's views about Ed Miliband.
But I don't want to focus on Labour/Unite relations exclusively. Unite campaigns on a whole range of issues – there is a full list on its website. And, contrary to the impression given by some in government, the battle over the government's plans to cut public sector pensions isn't over. There's more on Unite's stance here.
I'm also interested in McCluskey's wider views on the future of Unite and the role of trade unions generally. After McCluskey's election in November 2010 my colleague Seumas Milne said his victory was "a shot in the arm for anyone who wants to see a coherent campaign of mass opposition to Cameron and Clegg's avalanche of cuts and privatisation – and the development of a genuine political alternative". What does McCluskey have to say about that now?
I won't be able to use all the questions you suggest, but it is helpful to get ideas from others and it is useful to know what topics you find particularly interesting.