Once a friend and I were in his car and were T-boned by an idiot who didn't stop or look before pulling out of a junction in Deptford. It was entirely this guys fault and there were plenty of witnesses who voiced opinions in our favour. He then insisted on leaving his car in the middle of the junction to call the Police.
As he walked away my friend and I went to pull our car off to the side of the road as we were causing a complete obstruction to traffic.
At the sight of this the guy came running back and tried desperately to force my hands(bending my fingers back) from the car saying we had to leave the cars there for the Police to see. I calmly assured him that if we were in the wrong then we would accept what the Police had to say.
With this, and still leaving his car blocking all the traffic, he went to the phone box and rang the Police.
Seizing the oppertunity I ambled over to his car and saw he had left his keys in the ignition so took them out and put them in my pocket.
In short the Police arrived and gave him hell for leaving the car in the road. When he got to his car to move it he found the steering lock on and no keys. At this point I offered him his keys back.
OK I got some turse words from the attending officers who were a little amused but it was worth it for the look on the guys face, who couldn't say or do anything because the Police were there!!