Once you've joined Diamond Club you'll be enrolled as a Blue member. You'll receive an email detailing your membership number and a virtual Blue membership card. Once you've earned 3,000 membership status miles within 12 months, you'll reach Blue Plus status and you will receive a membership card (which you can use at all bmi self Check-in Machines) and complimentary food and preferential seating on bmi Heathrow routes that currently offer a paid for service.