You seem to have been a bit ahead of me. Basically when I was around the end of the high street things gradually ground to an almost complete halt; I saw when I did finally get down a side street that the cops had put a massive cordon around the embassy which also, well, closed down all progress. They did, as I said in my own journal, take down a barricade to let people down said side street but it was either that or have several hundred people take it down for them. It took me a good hour to get anywhere near the embassy.