The move will see the pre-tax price of return flights to New York cut from pounds 310 to pounds 140 and flights to Hong Kong slashed from pounds 569 to pounds 279.
The reductions are a direct response to British Airways' own cut-price offers which also offer discounts of 50 per cent on international flights. Members of the public must collect tokens to qualify for the discounted flights, which can be bought from 28 October.
Virgin's air fares have been deliberately set to undercut BA's discount offer by a few pounds and the offer runs from today until 28 October.
Mr Branson said yesterday: "We will never be beaten by BA on price and will always offer better quality." He added: "This is another war between Virgin and BA which proves that competition works and that the consumer is the ultimate victor."
A spokesman for BA echoed Mr Branson's comments. "We've always said, whether it's Richard Branson or anyone else, competition is healthy and it's the consumer who wins," he said.
But that was the end of any agreement between the two airlines and the BA spokesman pointed out that BA's offer covered 150 destinations and was "truly worldwide" while Virgin could only offer a handful of flights. "Clearly Richard Branson will only be able to fly to 12 places just because Virgin is much smaller than BA," he said.
But Mr Branson had his own criticism to make of BA's scheme. "Virgin's new fares are the cheapest across the Atlantic and to take advantage of them you don't have to collect tokens. You just need to call Virgin and book."
The BA spokesman also argued that the battle was not a true trans-Atlantic price war because Virgin had flights to far fewer US destinations than BA.
The price war will put immediate pressure on other airlines to try to match the BA and Virgin discounts.
Mr Branson admitted the offer was going to cost Virgin "a fortune", but a spokesman for the airline said the flights would still be profitable for Virgin.Reuse content