I was involved in an accident (in England, A259) this morning, with four vehicles (v1 to v4, v1 in front and me in v2) involved, in line and hit from behind. I was driving the second vehicle from the front. It happened when we slowed in traffic, and the vehicle in front of me (v1) had stopped or almost stopped. I was almost stationary safely short of him, when my car (vehicle 2) was hit from behind and pushed into v1 in front of me. After an obscenity filled pause I and v1 pulled ahead a little and on to the verge. We established that both our vehicles 1 and 2 had suffered no damage beyond a few superficial scratches.
However the van behind me, vehicle 3, I could see had had its front number plate knocked off. The last vehicle 4 now badly damaged at its front end, had been the source of the accident, having run at speed into the back of v3 and shunted us all forward. I did not look at the damage to v3, it was hidden by the wreckage of v4. Having established everyone ok, I and v1 went on, leaving the drivers of v3 and v4 to sort it out.
Should I have done more, like give them my details or especially should I have informed the police?