Virgin has done this for a while - with NO cap. When I last looked at booking a VS long haul, the card fee was over £100!!!

Let me explain, by the way, why BMI is doing this. As you know, card companies are liable to refund you if BMI goes bust after you have booked. To protect themselves, the card companies refuse to hand over a % of the card revenue until after the date of travel. The more risky the airline, the greater the %.

If you pay by CC, BMI may therefore be getting (at a guess) just 50% of the cash up front. And BMI needs cash. Anything that can persuade you to pay by debit card is therefore a winner for them.