999 is the United Kingdom's and Ireland's emergency telephone number, used alongside the EU standard 112. Either number can be used but 999 is more popular and better-known than 112. It is also the emergency telephone number in some Commonwealth countries (the rest use a variety of numbers, including 9-1-1). It is also used in Botswana, Ghana, the United Arab Emirates, Hong Kong, Macau, Malaysia, Singapore and Qatar.

It is an all-service number, meaning that it should be called in any situations where state-run emergency services are needed (this number is not there to be abused, we are NOT a pizza delivery service nor a taxi home, we are here to save your life if need be). The four main and best-known services are HM coastguard, fire brigade, police and ambulance. Other available services include mountain rescue and cave rescue (where locally relevant). Some situations such as a major car accident or a terrorist attack (including nuclear, biological, or chemical attacks) will require multiple and/or specialist services but the first point of call for reporting such incidents from the general public is still the 999 system. In some situations there will be specific instructions on nearby signs to notify some other authority of an emergency before calling 999. For example there are notices on bridges carrying railways over roads telling people that, if they see a road vehicle striking the bridge, they should call the railway authority (on a given number) first and then call 999 to inform the police.

In the UK, the number is operated by BT, Cable and Wireless, Kingston Communications and Global Crossing. These organisations forward calls to the appropriate emergency service for the location and incident; all calls to the number are made free of charge. The operation of 999 is co-ordinated by the 999 liaison committee.

Let's hope you never need to call us!