at the G8 in scotland a police officer threatened to shove a police hat up my arse and told me if they arrested me id be in pieces in a cell, i was told to leave scotland immediatley and not come back. all that for playing frisbee with a police hat!

This is an excerpt from a US website, I assume it must apply to the British.

Excerpt from:

 http://flexyourrights.org/

Street Stop Scenario

Scene from BUSTED
In any given public police encounter, with a few notable exceptions, the below rules will help protect your civil rights and improve your chances of leaving safely—so you don't have to be a legal expert to say and do the right thing.

1) Keep Your Private Items Out of View
This is common sense: Always keep any private items that you don't want others to see out of sight. Legally speaking, police do not need a search warrant in order to confiscate any illegal items that are in plain view.

2) Be Courteous & Non-Confrontational
If you are stopped by a police officer, remain calm. Don't ever -- under any circumstances -- talk back or raise your voice to a police officer. You have nothing to gain -- and everything to lose -- by escalating the hostility level of the encounter.

Even if the officers are being belligerent it's always in your best interest to remain calm, courteous and non-confrontational.

3) Determine the Reason You Have Been Stopped
Police may initiate a conversation with any citizen for any reason, however they may not detain you without "reasonable suspicion" that you are engaged in criminal activity. Ask the officer: "Why am I being stopped?" If the officer does not indicate that you are suspected of a specific crime, then this is a casual stop and you should be allowed to terminate the encounter at any time.

If the officer indicates that you are suspected of criminal activity, you are being detained. At this stage, the officer is attempting to find evidence on which to establish probable cause necessary to arrest you. Steps #4, #5, and #6 become extremely important at this point.

4) Just Say "No" to Warrantless Searches
Warning: If a police officer asks your permission to search, you are under no obligation to consent. The only reason he's asking you is because he doesn't have enough evidence to search without your consent. If you consent to a search request you give up one of the most important constitutional rights you have—your Fourth Amendment protection against unreasonable searches and seizures.

A majority of avoidable police searches occur because citizens naively waive their Fourth Amendment rights by consenting to warrantless searches. As a general rule, if a person consents to a warrantless search, the search automatically becomes reasonable and therefore legal. Consequently, whatever an officer finds during such a search can be used to convict the person.

Don't expect a police officer to tell you about your right not to consent. Police officers are not required by law to inform you of your rights before asking you to consent to a search. In addition, police officers are trained to use their authority to get people to consent to a search, and most people are predisposed to comply with any request a police officer makes. For example, the average motorist stopped by a police officer who asks them, "Would you mind if I search your vehicle, please?" will probably consent to the officer's search without realizing that they have every right to deny the officer's request.

If, for any reason you don't want the officer digging through your belongings, you should refuse to consent by saying something like, "Officer, I know you want to do your job, but I do not consent to any searches of my private property." If the officer still proceeds to search you and finds illegal contraband, your attorney can argue that the contraband was discovered through an illegal search and hence should be thrown out of court.

You should never hesitate to assert your constitutional rights. Just say "no!"

5) Determine if You Can Leave
You have the right to terminate an encounter with a police officer unless you are being detained under police custody or have been arrested. The general rule is that you don't have to answer any questions that the police ask you. This rule comes from the Fifth Amendment to the U.S. Constitution, which protects you against self-incrimination. If you cannot tell if you are allowed to leave, say to the officer, "I have to be on my way. Am I free to go?"

If the officer says "Yes," tell him to have a nice day, and leave immediately. If the officer's answer is ambiguous, or if he asks you another unrelated question, persist by asking "am I being detained, or can I go now?" If the officer says "No," you are being detained, and you may be placed under arrest. If this is the case, reassert your rights as outlined above, and follow Rules #6 and #7.

6) Do Not Answer Questions without Your Attorney Present
There is no reason to worry that your failure to answer the officer's questions will later be used against you. The truth is just the opposite: Anything you say can, and probably will, be used against you.

In just about any case imaginable, a person is best off not answering any questions about his involvement in anything illegal. Assert your Fifth and Sixth Amendment rights by saying these exact words: "Officer, I have nothing to say until I speak with a lawyer."

*Remember- If you do choose to answer any of the officer's questions, always be honest. Police are not easily tricked and will often become hostile if they feel disrespected. If you feel it is best not to answer truthfully, then don't say anything at all.

7) Do Not Physically Resist
If the police proceed to detain, search, or arrest you despite your wishes—do not physically resist. You may state clearly but non-confrontationally: "Officer, I am not resisting arrest and I do not consent to any searches." Or you may assert your rights by simply saying nothing until you can speak with an attorney.

Although the previous comment makes some good general points it is better to be informed about the legal issues relating to Stop and Search in this country.
Here is a web address containing good detailed information about proper procedure and individual rights in these situations:

www.yourrights.org.uk/your-rights/chapters/the-rights-of-suspects/stop-and-search/index.shtml

the website is maintained by Liberty.

in the UK the police have no right to take your details unless they have arrested you & charged you, or you are within a 'section' (44 or 60 - laws initially created to fight 'terrorism')

this means if a cop stops you and asks for your details, you are within your rights to refuse, and they cannot arrest for being unwilling to givr your details.

of course it may speed your situation if u do give them details. when I decide to, I usually mispell my name by 1 or 2 letters, so they cannot cross-reference appearances.

B

There is no obligation to provide names and address under either section 60 CJPOA 1994
( http://www.opsi.gov.uk/acts/acts1994/Ukpga_19940033_en_5.htm#mdiv60)

or section 44 of the Terorism act 2000
( http://www.opsi.gov.uk/acts/acts2000/00011--f.htm#44)

However, if you have ID on you, you're unlikely to be able to stop the police reading and noting it.