When it comes to national security and foreign policy they're expressly a propaganda outlet of the intelligence services and British (ie US directed) state these days.

They were far from perfect before but in the wake of the Snowdon leaks and the intelligence services making a show of not only smashing up their hardrives in the Guardian offices but threatening their journalists, the paper pivoted hard toward doing exactly as it was told. It's no longer a public trust, instead having being ran by a private board, none of whom are journalists anymore and several of which have intelligence ties. They were 'invited' to sit on the advisory panel that the intelligence services use to issue the new version of censorship D-notices, now called the Defense & Security Media Advisory Committee where the intelligence services commented about how much more 'cooperative' they'd become even compared to other leading newspapers like The Times.