The laws in the UK will likely have some differences to the laws in your own country. Equally, if you travel to another country – they will have different laws again. Not knowing that something is against the law is not an excuse for breaking it.
It is very rare for international students to have serious problems with the law but, just in case, here are some things that you should know.
The Police have the right to stop and search anyone they believe is behaving in a suspicious way. You should be polite if you are approached by the Police – answer any questions they ask truthfully and do not try to bribe them. A police officer who does not wear a uniform (plainclothes) should always show you their ID – if not, then you can ask to see it.
If you are arrested or have witnessed a crime, you will be asked to make a statement to the police. When this happens, you will tell your story to a police officer, who may ask many questions in order to make the statement exact. Once this is all written down you will be asked to sign it and say that it is accurate. You must never sign a document if you do not understand it.