So, Stephen Byers believes that Labour should "modernise" its links with the trade unions. That makes it quite clear that, no matter what they say in public and no matter how they attack Cameron for being a chameleon he's got them rattled by the direction he's taking the Tories.
Nothing, of course, will happen as a result of this story. As ever with Labour it's just a way of sending a "we're not so left-wing" message to key voters. What's interesting is that they feel they have to say.
I can't help but think it won't make Brown uncomfortable either. Clear "New" Water for a challenger anyone?