David Miliband will suggest that the next generation is "up for grabs", in a speech this evening.
Delivering the Speaker's Lecture, the former foreign secretary will warn that "politics is more volatile in a time of crisis".
But he will argue that we are in a "crisis of governability" (similar to the politics of the 1970s) which comes from "the weakness of governance abroad".
Labour sources described his speech as a call for "political reform in response to the economic crisis".
Interestingly, this includes some reforms specific to Parliament, including more topical questions to ministers.
The speech will back Labour to win the 2015 election. But Miliband will argue that voters can also turn away from mainstream parties altogether, rather than just turn to opposition.
I will post the full speech here later.