The police had received orders to avoid confrontation. They had no riot shields or helmets, and made no effort to remove sticks or masks from anyone, as far as I know. I have heard that they did hassle some known activists (one for carrying paint, which he claimed was to make banners). One activist was arrested for graffiting, but he did sign it with his name! The police did prevent people from leaving the agreed march route, often standing behind metal barriers with police vans behind. This was partially to avoid side-streets becoming open sewers... At one point police did form a line to stop the flow of the march near Picadilly Circus, but I believe that this was to ease the flow as the marches converged, since the block lasted less than a minute. Buses were hired by local Stop the War coalitions and other anti-war groups, but were not laid on by the government. No extra trains were laid on, but services were as usual.

At the US embassy there was heavy police presence, and protesters who formed up in a line were physically pushed back by the police.

A very large part of London was closed, including several tube stations. The march route was two-pronged, one starting at Gower St by the British Museum, and the other starting at the Thames at Embankment. Both marches converged on Picadilly Circus and headed up to Hyde Park for the rally.