You should have a test if you think you have exposed yourself to the risk of contracting HIV – for example unprotected sex with someone who is HIV positive or who doesn’t know their status.
Sexually active gay or bisexual men should take a test at least once a year – and more regularly if you have unprotected anal sex with new or casual partners.
It’s also recommended that you take a HIV test as part of a routine sexual health screening.
If you have had unprotected sex recently and you’ve experienced severe flu like symptoms (for example sore throat and fever) you should get tested as soon as possible.
Details of where you can test are given in an earlier answer