LONDON — Comcast wants to upend the Walt Disney Company’s empire-building plans, and a jewel of Europe’s media industry could give it an opening.

As both companies pursue a bigger-is-better strategy, they are vying for control of the British satellite broadcaster Sky. A regulatory ruling on Tuesday could be a prelude to a bidding war over the company — and to a larger fight over 21st Century Fox.

The deal-making machinations, which have unfolded in two countries for over a year, are complicated and interconnected. Disney has offered to buy Fox, which already owns part of Sky and has offered to buy the rest. Comcast has made plays for both Fox and Sky, all with the goal of causing trouble for Disney.

Fox’s bid for Sky had been held up in regulatory limbo in Britain for months over concerns that it would give Fox’s chairman, Rupert Murdoch, too much control over the country’s media. On Tuesday, Britain’s culture secretary, Matthew Hancock, ruled that Fox could proceed with its bid, provided that it sold Sky News, the broadcaster’s 24-hour news channel.