Calling the emergency medical services (EMS) is simply done by calling 999 or 112. 112 is the European number but it works in the UK as well. They will ask you what service you require: Fire, Ambulance, Police or all of them. Speak clearly and answer all questions as best as you can. They will need your location but they may be able to track you from your phone number. You can register to call the EMS by text message if you are hard of hearing.