While Sky's directors have approved the deal and are willing to recommend it to stakeholders, it's not quite in the bag. In a document announcing the bid, it's stressed that "there can be no certainty that an offer will be made by 21st Century Fox, nor as to the terms of any such offer." That means the provisional agreement is just that -- provisional. For now, anyway.

Sky's media empire stretches further than the UK. In 2014, the company bought Sky Italia and the bulk of Sky Deutschland from 21st Century Fox for £4.9 billion ($8.3 billion). Should the new takeover go through, these businesses would fall back under 21st Century Fox's influence. Its global reach would be considerable, and give the company a large platform to distribute content and services. Before the papers can be signed, however, we suspect some regulatory bodies will want to examine the deal and its impact on competition, both in the UK and on an international stage.