They've given the massed ranks against them absolutely nothing to get their teeth into, while setting traps a plenty for their competitors. They could be banging on about the 500 excess deaths a week attributable to tory cuts, the shit in your rivers, the ravaged criminal justice system, the absence of affordable housing, the rocketing cost of essential services and even food......but they know that they need to proceed with care, and not scare the horses. When the country is going down for the third time, it's not the moment to bang on about your bronze medalion, and how there used to be life guards. You have to be prepared to get wet. On that basis I think that labour have been entirely serious. Very impressive.
What's the most scandalous labour smear and lie? (I don't exactly pour over mainstream coverage, but I'm going to bet I can source you ten worse from 'the other side' for every one you can come up with.)