Well not quite free, you and your Mrs ,Ms or Russian bint need to both sign up for a BA premium american express card. Annual cost is 150 quid but the first thing you buy with the card gives you 6000 miles free flight. So what is the legal side ( I looked at the long bit on the site and you can close the account after paying off the card)... As I said. So get card, buy something with it, get the 6000 miles , book ticket, go on trip . Pay off and close account. What is the legal/credit side to doing this . Is there a trap?