While it's Ed Miliband's comments on Google and tax avoidance that will inevitably attract the most media attention, by far the more interesting section of his speech at the company's "Big Tent" event at The Grove hotel in Hertfordshire was on capitalism and socialism.

The Labour leader opened his address by showing four pictures, of Ralph Miliband, Willy Wonka, Margaret Hodge and Google, and, in the manner of Have I Got News For You, asking the audience to guess the odd one out. The answer, he continued, was his dad "because he’s the only one who thought that the route to a fair society was not through capitalism but through socialism based on public ownership."

In a reference to Labour's old clause IV, which called for "common ownership of the means of production, distribution and exchange", Miliband added that "It wasn’t just my dad who thought it, of course. Until 1995 this view was enshrined on the membership card of the party I now lead." He then praised Tony Blair, the man who recently warned him in the NS not "to tack left on tax and spending", for scrapping it "because nationalising the major industries is not the route to a fair society." Though it may be surprising that a Labour leader still feels the need to say so, capitalism is the only game in town.

But Miliband was clear that this doesn't preclude debate about what kind of capitalism Britain should adopt. After all, the Americans, the Chinese and the Swedish all do capitalism but they do so in very different ways. For Miliband, returning to the theme of his 2011 Labour conference speech, the choice is not between capitalism and socialism but between "responsible capitalism" and "irresponsible capitalism". Citing The Simpsons' Mr Burns as an example of a neglectful capitalist ("Of course, he is a cartoon character," he helpfully noted), he argued:

[T]there is a choice to make. A choice between an “irresponsible capitalism” which sees huge gaps between the richest and the poorest, power concentrated in a few hands, and people are just in it for the fast buck whatever the consequences. And a “responsible capitalism”, and this is an agenda being led by business, where companies pursues profit but we also have an equal society, power is in the hands of the many and where we recognise our responsibilities to each other. And my case is a “responsible capitalism” isn’t only fairer but we’re more likely to succeed as a country with it.

By adopting this stance, Miliband is taking on both the socialist left, for whom "responsible capitalism" is an oxymoron, and the neoliberal right, for whom a deregulated market economy is the only guarantee of prosperity.

In the Q&A that followed, no one asked the Labour leader whether he would still describe himself as a "socialist" (as he did in November 2010), but on whether socialism has any relevance today, it's worth highlighting the smart answer he gave to the Telegraph's Charles Moore last year. After he was asked whether "the great lesson from his parents is ‘that socialism was a god that failed?'", Miliband replied that it was not a rigid economic doctrine, but "a set of values", and "a tale that never ends" since "While there’s capitalism, there’ll be socialism, because there is always a response to injustice."