As the Beeb in particular go bananas over the 25th anniversary of the Miners' Strike, I think it's important to remember a particularly pisspoor event in journalistic history. It's also apt to mention it now with Roger Cook claiming to speak up for journalism in the wake of ITV cuts.
I don't think it'll be mentioned amid all this excitement, but The Cook Report, and Roy "Media Ethics" Greenslade's Mirror, published a pack of lies about former NUM boss Arthur Scargill, based on shaky uncorroborated testimony from someone who may or may not have had links to MI5, supposition, bollocks and made-up stuff.
The 'reveal' to this bullshit smear only took place several years later, meaning a safe amount of time had passed, safe enough for the idea of Scargill's 'Libyan mortgage' to have been accepted as, if not fact, then certainly fishy, by a lot of people. It was a particularly shabby affair. Greenslade has said sorry, but he's the only one, as far as I'm aware, and that's not really good enough anyway. The lesson to learn for the 'professional journalists' and 'real' press is: only publish if you're completely sure. But somehow I don't think that lesson's been learned at all; rather, it's a case of Scargill didn't sue, so they got away with it, and the smears stuck.