Andyvon, if you phoned from either your home phone or a contract mobile phone the number will display on the computer screen of the operator taking the call, while you are talking the computers are set to bring up your address and details if available making it easier for the emergency services to get help to you if you require it. Some people are in such a panic they cant give their name let alone address, so the system is a great help. Likewise the police have access to the vehicle data base so any vehicle registered to you can be seen quite easily, they use this to keep an eye out for drivers who are uninsured, have no tax or MOT, or are disqualified from driving. People who worry about the police having access to so much info had better stop using computers, credit/debit cards, store loyalty cards or even owning a house and paying utility bills. All of these leave traces of your identity with a multitude of organisations who are a lot less trustworthy than the emergency service response centres.
The innocent having nothing to hide, the guilty want everyone to believe they have nothing to hide!!