Oborne’s article i mentioned earlier is actually quite good on this (astonishingly), gives some good examples of how the government has been putting out lies unofficially from ‘sources’ via journalists and then denying all knowledge and accountability when asked officially.
eg he talks about how when Rudd resigned she complained that she was not given access to legal documents she had requested access to, an anonymous source told journos that ‘actually she had every chance to view these documents at any time’, while the official Tory response was ‘no comment’. they were able to put it out into public consciousness that Rudd is a liar without having to be held to account for it (i know Rudd is awful and you do get the sense that Oborne is very willing to side with her either way, but i don’t see any reason to believe anonymous sources over her, tbh)