Emergency Hormonal contraception or more commonly known as the "Morning-after pill" is used to prevent pregnancy after unprotected sex
There are two brands (Levonelle and EllaOne) of emergency contraceptive pill in the UK; one that has to be taken within 72 hours (3 days) of unprotected sex and one that has to be taken within 120 hours (5 days).
Emergency contraception works by preventing ovulation. It is more effective the sooner you take it after unprotected sex. There are very few side effects to the morning after pill.