Green Day (Warner Bros)

Nearly five years after American Idiot, the US has a new president and, apparently, some hope for the future.

No one’s told Green Day.

21st Century Breakdown continues the protest-song theme of its 12 million-selling predecessor, with an extra quirk: this is Green Day’s first rock opera. Which means what, exactly?

Firstly, that it’s split, rather grandly, into three acts, complete with recurring hooks and big lighter-waving piano ballads.

Secondly, that it’s long. Very long, 70 minutes.

But in terms of what it means for Green Day’s sound, the answer is not much.

Sure, a few songs are a little longer than normal, with tempo changes to befuddle the moshpits.

Butch Vig’s production gives them a little more breathing room, too.

But while it’s not without its successes, this sprawling mess is a straight-ahead punk-rock album by a group without the ability to match its ambition (the 21st-century Clash, in other words), ultimately rather less than the sum of its parts. WILL FULFORD-JONES