It's basically the UK's Fox News but perhaps even less impartial as it let's politicians host shows - it definitely feels like an attempt to shift the Overton Window to the right. Quite why it hasn't been sanctioned by Ofcom is unclear.

There's a good overview here.

edit: this is the key part for me:

Around this time, the charity Hope not Hate published an investigation reporting that Paul Marshall, the founder of news and commentary website UnHerd and co-owner of what it called the “right-wing channel GB News”, had used his X account in a way that suggests “he holds a deeply disturbing view of modern Britain.”

The holding company that owns GB News is called All Perspectives Ltd. It has two major shareholders: Legatum Ltd and Sir Paul, who own 41.2 per cent of the company each. Marshall’s fortune is put at an estimated £800m from his career as a hedge fund manager. He does not post on X much. He does, however, retweet and “like” what Hope not Hate described as “notorious hate accounts such as the Britain First deputy leader Ashlea Simon, American anti-Muslim campaigner Amy Mek and the shady Italian anti-migration account Radio Genoa.”

Marshall, who is also bidding for ownership of the Telegraph and the Spectator, “has repeatedly liked and retweeted extremist content from an array of far-right and conspiracy theorist accounts,” the charity found. A representative for Marshall issued a statement noting that “as most X/Twitter users know, it can be a fountain of ideas, but some of it is of uncertain quality and all his posts have now been deleted to avoid any further misunderstanding.” What was “misunderstood” was not explained, but if the head honcho likes and retweets views like this, then the cast of eccentrics and Looney Tunes characters given airtime on his channel begins to make more sense.

Here is the Hope Not Hate article that draws from.