Leading article: Ed Miliband: the next generation

Ed Miliband did not come to bury everything about New Labour in his conference speech in Manchester yesterday. But the new leader did come to bury the former government's most egregious mistakes. On Iraq, he admitted that "we were wrong". When it came to markets "we became naïve". On civil liberties "we seemed too casual".

There was very little that would have pleased Tony Blair in this speech and much that would have irked Gordon Brown. Indeed, the constant references (14 in all) to a "new generation" in charge of Labour were a clear attempt to draw a line under the long Blair/Brown era. Mr Miliband was justified in doing so, given how stale those old factional battles have become. He was also right to challenge that "old thinking" on everything from crime to international alliances that led Labour down so many blind alleys during its time in power.

The new Labour leader was sensible, too, to confound those who have attempted to present him as some sort of unreconstructed leftist; a creature of the unions which played a crucial role in delivering his leadership victory over his brother. Mr Miliband stressed that he was not about pander to the left of his party. He warned that there would be Coalition cuts in the years to come that Labour would not like, but that he would be compelled to support for the sake of the party's fiscal credibility. He criticised "overblown rhetoric about waves of irresponsible strikes" and made it clear that he understood how badly Labour had done at the election. None of this was telling his audience what it wanted to hear.

Mr Miliband also demonstrated that he is a political grown-up, not a tribal rabble-rouser, when he said that he would resist the urge to accuse the Coalition of being "soft on crime" over its review of sentencing. And, again wisely, he did nothing to close down the possibility of a future coalition with the Liberal Democrats. His promise to campaign for electoral reform in next year's referendum on the Alternative Vote could even help open the way to such a partnership.

But when it comes to what Mr Miliband is offering to the electorate, the picture remains disconcertingly fuzzy. He did not give any indication of which way he will jump on reducing the deficit, whether to Ed Balls's radicalism or Alistair Darling's relative conservatism. He said he recognised popular concerns about immigration, in particular its effect on wages. Yet the "proper labour standards" that Mr Miliband spoke of, though welcome, would be unlikely to prevent competition keeping a lid on wages.

Mr Miliband said that, on the environment, he would not be bound by what focus groups say will be acceptable; that he would be ready to show leadership, even if it did not win immediate votes. That determination is, of course, welcome. But Mr Miliband told us nothing of what emission-cutting proposals he might bring forward.

The new leader spoke of "the good society" – a riposte to David Cameron's "big society" slogan – but he did not specify how it would be constructed. There was vague talk of preserving the distinctiveness of high streets, delivering a living wage and the promotion of "family-friendly employment". But all of these ideas raise the question: how?

Of course, this lightness on policy was inevitable given that Mr Miliband had only been in the leadership harness for three days. But he will need to fill these gaps if he is to be a credible alternative Prime Minister. Mr Miliband made the right noises about the past and some promising indications about the future. It was a solid, if not spectacular, debut. His next – urgent – tasks are to define his policies and to find his true voice.