In a blog posted on his website after it was circulated to Virgin Atlantic and Virgin Holidays staff, Branson said he viewed the airline – founded 35 years ago – as “one of his children”.

After authorities green lighted the British Airways-American Airlines partnership, Branson said Virgin needed to form a “strong alliance of our own”.

“Remarkably, the most impressive of the large airlines, Delta, was there to form an alliance with us,” said Branson. “And they have been the best partners we could have wished for.

“That still left our family in control and owning the airline. But with BA’s clout in Europe we needed further partners to provide feed for the Virgin Atlantic network, and discussions started with Air France-KLM. Agreement in principle was reached in May 2017.

“To get the deal done, we initially thought our family would need to reduce its shareholding in Virgin Atlantic. I was willing to do so, reluctantly, to guarantee the long-term success of Virgin Atlantic.”

Branson went on to confirm the tie-up has now been approved by various competition authorities, the last of these being the US Department of Transport, who, Branson said, gave antitrust immunity to the new joint venture on 21 November.

“Importantly following this news, we have agreed (subject to contract) with our new joint venture partners, that our family will continue to hold the 51% of Virgin Atlantic shares we own. We’ll also continue to work extremely closely with our partners investing together in a thriving airline and holiday company.”

He added: “Just like in 2008, we’re at a point in time where we need to stand up for fair competition for the benefit of British customers and businesses.

“So we’ll continue to be vocal throughout 2020 with our Two Flag Carriers campaign, urging ministers to grasp the once-in-a-generation opportunity to shake up the status quo at Heathrow. Because Britain deserves better.”