Airlines' link under fire from Branson

The plan, supported by the US Department of Transportation, would see the airlines work together to share costs.

That could allow them to offer lower fares on more routes, and reduced travel and connection times but they would have to give up four takeoff and landing slots between Heathrow and the US in return.

Sir Richard said the decision beggared belief.

He said: "The US Department of Justice, who are the experts in competition issues, called for strict remedies to protect the public interest, because the alliance will blatantly harm competition and the consumer. The Department of Transportation has chosen to stick two fingers up at them.

"Millions of transatlantic travellers will be adversely affected if the alliance receives final approval.

"In my personal opinion, this draft decision is a real kick in the teeth for consumers and they will be paying the price for it for years to come."

The US Department of Transportation will decide whether to give the plan immunity from anti-trust legislation after a 60-day consultation period.

A BA spokesman said British Airways, American Airlines and Iberia planned to operate a joint business between North America and Europe. Closer cooperation would benefit customers with more travel choices and convenient schedules.