with the introduction of its new aircraft.

BA spokeswoman Sallie Singleton said: "The fare that will get the most attention is a brand new 90-day APEX featuring fares as low as $524 for mid-week, low season travel for passengers willing to book three months in advance.

"The highest level will be $849 for mid-summer, week-end travel.'' The airline will guarantee that this 90 day fare is the best possible one for the date a traveller flies.

BA manager Philip Troake said: "Furthermore, we are prepared to give a guarantee that the 90 day APEX fare will be our best possible fare. Should the fare for a passenger's travel date drop, British Airways will refund the difference,'' said Mr. Troake.