Billionaire entrepreneur Richard Branson has found a new partner for his Virgin Atlantic Airways group as he attempts to challenge British Airways' dominance of long-haul flights from London's Heathrow Airport.

US carrier Delta Airlines, the country's second largest, said today it was purchasing a 49 percent stake in Virgin Atlantic, currently held by Singapore Airlines, for around $360m (£223m/€277m).Singapore Airlines paid just under $1bn for the stake in 1999.

The two carriers also announced a joint-venture that would lead to more than 20 trans-Atlantic flights each day from Heathrow.

The tie-up will "provide a more effective competitor between North America and the U.K., particularly on the New York-London route, which is the largest airline route between the U.S. and Europe," said Delta CEO Richard Anderson said in a statement published Tuesday.

Branson, the chariman who founded the airline nearly 30 years ago, said the deal "signals the start of a new era of expansion, financial growth and many opportunities."

Virgin booked an £80.2m loss last year thanks in part to high fuel prices, Europe's on-going recession and the stiff competition created by BA's alliance with American Airlines.

The deal comes just a day after Branson, 62, said he was prepared to wager £1 million on the survival of his Virgin Atlantic brand after comments from Willie Walsh, the CEO of BA owner International Airlines Group, suggested otherwise.

Branson said he would distribute the cash to BA employees saying on his company blog post: Sorry, BA, we're not going anywhere!

"The last time BA had to make a settlement to me for damages (in part for spreading not dissimilar false rumours) I split the money amongst our staff. Rather than suing them on this occasion, I will pay £1 million to their staff if Virgin Atlantic disappears within say five years. If not, BA pays our staff £1 million."