This program gets you a free companion ticket in conjunction with the purchase of a full-fare business or first class ticket on any of 22 airlines. Virgin isn't on the list, but Continental (BusinessFirst) is. CO has no blackout dates in the program.

According to my materials, the program is for US-based cardholders, tickets must be purchased in the US and travel must originate in the US, so you may be out of luck leaving from LHR. There may be a comparable program for UK members that I'm not aware of.

For more information, try www.americanexpress.com/platinum (in my experience, this site works better with IE than with Netscape; it doesn't say anything about a program for members outside the US) or call 800-648-4423, toll-free in the US.