to me about two hours ago now. it is pretty clear that at times like this the police, their responsibility primarily is to ensure the safety of the public. we have seen that the course of our live coverage tonight. police pushing back members of the public. moving back out and actually i just want to break in for a second and bring you this. theresa may, the prime minister. she is on her way back to london. she has said the terrible incident is being treated in her words as a potential act of terrorism. that confirming which we heard from a correspondent mark white a little earlier today. that that was the working assumption.and understandably so. as i was mentioning, the police have been very keen to move members of the public out of the area quickly. we saw pictures from the