I don’t know anyone outside my organisation who could be a referee. What should I do?

Referees are people who know you and know broadly about the work you have been doing during the qualifying period, and are in a position to judge both the quality of the work and your professional approach. So you need to make contact with other members of the Institute and ask if they can help, it's a good reason for attending the Annual Conference and for joining a Regional Group or Special Interest Group, and for keeping in contact with other members you've met.

Remember, the referee needs to know you and your work, so you may need to plan to get to know them in advance of submitting your application. If your prospective referees are not up-to-date with your most recent work, you can always bring them up-to-date before you submit your application.