If you've been a victim of a crime or thing you've seen one happening, you should report it to the police straight away. Keeping it to yourself would mean that your information couldn't be used to prevent and stop crime in your local community.
If you've just been mugged, attacked or if you've just seen a crime being committed, then you should ring 999 as soon as possible.
Once you've been put through, a police officer will ask you to describe what has happened and where you are. They may also ask you if any of the other emergency services, like the ambulance service, need to know about the situation.
If it is an emergency and you need urgent attention, a police officer will arrive. If you've been a victim then they'll be able to calm you down and help you with anything you may need.
If you want to let the police know about a minor crime like a stolen mobile phone, you should go to your nearest police station to report it or call your local police authority. You can find their number in the telephone directory.
By not using 999 for minor incidents, you're making sure that people in genuine emergency situations will be able to contact the police quickly and more efficiently. You can also report them to your local authority online.
Non-emergency incidents include reporting vandalism, graffiti, abandoned cars and other examples of anti-social behaviour.
Whether you reported an emergency or non-emergency, you will probably have to give a statement to the police. You'll have to tell an officer what happened to you or what you saw. As you tell them, they may ask you questions or ask you to repeat yourself to make sure the statement is as accurate and as detailed as possible.
When you've finished giving a statement, the police will then usually read it back to you to make sure that their written account matches yours. If you agree, you'll sign the statement and get a crime reference number. You'll need to keep this if you want to contact the police about the same incident in the future.
If you're reporting a theft, you'll also need to use this reference number if you're making an insurance claim.
Sometimes you may have witnessed a crime taking place and recognised the people doing it or you may have information that you don't want to give to the police in person.
If you're nervous about what might happen if people find out you've contacted the police and you want to remain anonymous, you can call Crimestoppers. Your information will be recorded by a trained operator and will be passed on to the police.
If you do give information to Crimestoppers, your call will never be traced and you won't have to give information in court or give a full statement, no matter how useful it turns out to be.
You can call Crimestoppers at any time on 0800 555 111.