I booked a flight from Singapore to London on Expedia to fly on British Airways (BA) 3 months and forgot to put my Avios membership number, can I still get the points on the flight?

Looks like you have not fly yet. You can definitely add your Avios membership numbers to your flight details. Just call in or email them as soon as you can to include your membership numbers to your flight details.

Hi, it looks like you have not flown the flight yet, since you mentioned that it is 3 months later. In that case, just give your FFP number to the check in agent for seamless accrual of miles.

Yes, they can backdate your points . just contact their customer support

Yes you can. If you have not flew, just ask the agent at the check in counter.

If you have, drop them an email with your reference number.

Cheers