LONDON (AP) — A quartet of former and current British Airways PLC executives pleaded not guilty yesterday to alleged price-fixing of fuel surcharges with Virgin Atlantic Airways, denying charges that can carry prison sentences.

BA former head of sales Andrew Crawley, former commercial director Martin George, former communications head Iain Burns, and former UK and Ireland sales chief Alan Burnett all denied the so-called "cartel offence" in an appearance at London's Southwark Crown Court. Crawley has since been promoted to sales and marketing director, while the other three men no longer work for the airline.

BA already has been fined a total of $550 million by British and US authorities over the allegations that it colluded with its rival over fuel surcharges on long-haul flights between July 2004 and January 2006.

Virgin Atlantic was granted immunity from charges after bringing the matter to the attention of the Office of Fair Trading.

In an e-mailed statement yesterday, Virgin Atlantic chief executive Steve Ridgeway indicated he knew about the alleged collusion.

"I apologise unreservedly for my involvement in this case," Ridgeway said. "Although I did not have any direct contact with BA in relation to passenger fuel surcharges I regret that, on becoming aware of the discussions, I did not take steps to stop them."

Ridgeway added he had cooperated fully with competition authorities since 2006 and had put in place a training programme to ensure all his employees understood and followed competition laws. BA has declined to comment on the court case. The direct charges brought by the OFT against the four BA executives allege they "dishonestly agreed with others to make or implement arrangements ... which directly or indirectly" fixed prices charged by BA and Virgin Atlantic.

If found guilty, they face up to five years' imprisonment and/or an unlimited fine.

All four men were released on unconditional bail until the start of the trial, listed for January 18, 2010.

However, the men are unlikely to be extradited to the United States, where a criminal investigation is still ongoing, because anyone acquitted or convicted of price-fixing in Britain cannot be charged with the same offence across the Atlantic under double jeopardy rules.