A minor clash between protesters and police has taken place, amid a mainly peaceful start to the marches and rallies.
About 20 campaigners attempted to break through police lines outside the central London headquarters of arms manufacturer Lockheed Martin.

About 200 people were demonstrating outside Lockheed Martin in High Holborn, when trouble erupted at around 1430 BST.

BBC News Online's Dominic Casciani said: "They charged police officers who were not wearing riot gear, before being pushed back by police reinforcements."

Some protesters unfurled flags and staged a sit-down protest in the middle of the road.

The protesters have now been contained within heavy police lines, bringing traffic in the area to a standstill.

Police have been issued special powers that allow them to contain protesters until they agree to disperse from the area on a route defined by police.

The senior police officer at the scene said protesters would be allowed to move on only if they agreed to go to Trafalgar Square.