LONDON — The Walt Disney Company offered to buy Sky News on Tuesday — but not because the British news channel is core to Disney’s business.

Instead, the offer is meant to help Rupert Murdoch’s 21st Century Fox buy full control of Sky News’s parent company, the broadcaster Sky, a deal that has languished amid concern here in Britain that Mr. Murdoch could assume too much control over the country’s media.

Disney has a stake in the outcome of that transaction. It agreed late last year to buy the bulk of Fox’s assets — including Mr. Murdoch’s international broadcasting operations, of which Sky is a part — for $52.4 billion. And it is competing against Comcast, the American cable giant that plans to make its own bid for control of Sky.

Since unveiling the 21st Century Fox bid in 2016 for the 61 percent of Sky that it did not already own, Mr. Murdoch has faced sharp questions over whether he would oversee too much of the media in Britain. His existing properties, including the newspapers The Sun and The Times of London, reach a third of British consumers. And he took fire for the phone-hacking scandal that led to the closing of The News of the World, the first newspaper that he acquired in Britain. (That controversy forced him to back off an earlier bid for full control of Sky.)