References are usually requested automatically for all short-listed applicants, so you will need to indicate on your application form if you do not wish your referees to be contacted prior to interview.
Both referees should be willing to comment on your suitability for the job in question. If you are or have been employed, one should be your present or most recent employer. If you have never worked or haven't worked for some time, think of someone who is able to say something constructive and relevant about you.
When you are completing the reference section in the application form, you must indicate whether the referee is your current employer, previous employer or someone providing a character reference.
No appointment will be confirmed without satisfactory references.