If you do not have any symptoms but would like to be tested for sexually transmitted infection, the NHS now offers the opportunity to do this at home via a postal self testing kit. Please see the Sexual Health London website for details.
If you are having symptoms which you are concerned might be due to a sexually transmitted infection please make an appointment with a GP or practice nurse or attend a sexual health clinic:
there are a number of sexual health (GUM) clinics in central and north London offer testing and treatment of all sexually transmitted infections (STIs/STDs), including HIV tests. You do not need a referral from your GP.