Why would Rupert Murdoch pounce on Sky now? First, because he was only ever biding his time after the humiliation of the failed bid in 2011. As 21st Century Fox said in its formal announcement, it has long regarded its 39% shareholding as “not a natural end position”.

Second, the fall in sterling after the vote for Brexit has played to Murdoch’s advantage. US bidders for UK assets start with the wind at their back. 21st Century earns its profits in dollars that, in sterling terms, are worth 15% more than they were in June.

Third, Sky’s share price has been sliding all year as the City has fretted about competition from BT, Netflix and Amazon. That has created an opening to put a cash offer on the table that is generous by conventional City yardsticks. At £10.75-a-share, Sky would be bagged at a valuation that was seen as recently as February but, critically, the price is 40% higher than this week’s share price. Cash bids at that level of premium tend to succeed, especially when there are no other bidders in town.

Sky’s independent directors have already agreed the price is fair, which puts 21st Century Fox in a stronger position than News Corporation in 2011. Back then, the independents said they would not accept less than 800p, but the final haggling over price never happened.

Could regulators still intervene and block the deal? It is possible. Since 2011, Sky Italia and Sky Deutschland have been folded into the UK company. That means Brussels, which sometimes springs surprises, especially on US companies, could find a way to get involved.

But Murdoch will think he has little to fear from the UK end. News Corp pulled its bid in 2011 after weeks of revelations about phone hacking at the News of the World but he has split his media empire in two since then. The UK newspapers are housed in the company that carries the old News Corp name. This fresh offer comes from 21st Century Fox, the US-listed company that owns a Hollywood studio and the Fox TV network and had nothing to do with phone hacking in the UK.

Murdoch has also been around the track on media plurality protections. Back in 2011, Jeremy Hunt, culture secretary at the time, wanted Sky News to be ringfenced to protect its editorial independence. Murdoch was willing to accept that condition at the time and would surely be happy to do so again. He is more interested in ensuring Sky stays in the big league of global media companies as AT&T prepares to buy Time Warner and the newcomers like Netflix and Amazon ramp up their original content.

Murdoch will also have noted there was minimal political fuss in the UK when his son James returned as chairman of Sky earlier this year. Outside shareholders in Sky protested at the first opportunity – a majority either opposed or abstained in October’s vote on the reappointment – but Westminster barely seemed to notice.