When a police officer breaks the law, he in turn becomes a criminal to some degree. The badge, uniform and gun do not make this any different. What makes it different is the mentality and mindset of fellow law enforcement personnel, attorneys and judges. As a cop in Va, we had an officer who was corrupt. The Commonwealth Attorney even told the Police Chief that he would never try a case that this officer brought forth. So what happened, this cop was put behind a desk, given a promotion to Lieutenant and a pay-raise, not fired and arrested. The fact is when a citizen gets involved with an officer the legal system most times makes the assumption that the cop is correct based solely on he or she being a cop. They are considered to be more credible that the general public and themselves believe that they have rights above the general public. And in many situations, unless an officer's conduct/wrong doing is brought before the public, then any actions against them will likely be minimal or light.
Many cops bank on the fact that the average citizen does not know the law. They use this to their advantage when dealing with the public.
Example: A friend and I went out for a drink a while back. He was pulled over for suspected DUI. As he was being tested the other officer came to the passenger side and began demanding info and ID from me. He was in no way being polite or professional. In my opinion anyways. I sat there looked at him and asked him why, was he planning on charging me with anything. He asked me if I had done anything illegal. I told him that I was nothing more than a passenger and that as a prior cop myself I was just ensuring to protect myself and my rights. This is when his attitude change 180. I was able to get out of the car and even speak with my friend for 20 min before they took him to booking. The fact is when they thought that I was an ignorant citizen, they chose to treat me one way. Yet when they realized that I knew better, they treated me different and afforded my courtesies that I know they would not have done before hand. And to top it all off, when we went to court to hear the judge, (I was there for moral support) the pros. atty said that in the officers statement that my friend had pulled in front of a city bus. Yet it was 230 in the morning and the buses had stopped running and if this was a fact, then they chose to wait and tail us for 5 min before pulling us over. Even though he had apparently, recklessly pulled out in front of a bus.
The fact is not all cops are bad, but not all are good either, and they will take advantage of you just as quickly as anyone else.

An excellent situation to point out in this thread would be Abu Ghraib. I just spent a month in field training, and we had all sorts of briefings and classes regarding civilians in country. I had a couple of chances to put such things to the test. One of the things is to always verify who you're dealing with. The other is that we are not to go out "guns blazing" every time we face an unknown vehicle. The third is to not hesitate to use force when necessary. My platoon did good, with only one glitch the entire time. That would be the lack of force when necessary. I got a good comment for making sure I properly ID'ed a target before firing. Being a good cop is like being a good soldier. You stay within the rules, but you are always willing to use the force necessary to do your job. And when off duty, you behave as if you're off duty, which is to say, another "civilian" on the streets. Even if you are doing something job related.

I don't know if the homeowner has the 'right to resist' in the UK. Does anybody else know?